Here are some tips that can help you out while starting out:
https://www.chess.com/blog/nklristic/the-beginners-tale-first-steps-to-chess-improvement
Good luck on your chess improvement.
Learning chess @ 40. Please help me make a plan.

@NotYourCentipawn - That's a good idea. Thanks.
@nklristic - Got some useful ideas going through the link. Thanks a lot. I am also a runner like you - though no ultras yet .
General question to everyone :
1. What fraction of my chess time should be allocated to each of the chess activities (General Studying, Tactics, Playing Games, Analysis, etc.)? In other words, if I am spending about 45mins a day on Chess, what and how should I be doing things in order to get the most out of my efforts.
2. How should chess software (Stockfish 14 as suggested by @NotyourCentipawn) be used at this stage?
My 30 days chess target is to skim through Soviet Chess Primer, solve 100 puzzles from the puzzle book, play and analyze 2 classical games (1 per week), and play and analyze 8 rapid games (2 games per week). Currently, I am 15 days into this, and have skimmed about a quarter of the Primer book, solved ~40 puzzles, and will be playing my first games over this weekend. So far, I haven't used computers at all and haven't even been playing on physical a chess board.
Please let me know your thoughts.

Welcome to the world of chess!
Hi! My name is Lauren Goodkind and I’m a respected chess coach and chess YouTuber based in California:
https://www.youtube.com/channel/UCP5SPSG_sWSYPjqJYMNwL_Q
I have tips and resources to help you improve your chess skills so you can win more games.
-I offer a free beginner’s free eBook on my website, in case you are interested. The book is about asking questions before each move.
-Learn basic tactics such as the fork, discovered attack, pin, and more. I offer interactive puzzles on my website:
-I recommend two books for you: “50 Poison Pieces” and “Queen For A Day: The Girl’s Guide To Chess Mastery.” Both books are available on Amazon.com. Both books are endorsed by chess masters!
-If you are serious about chess, I highly recommend you hiring a chess coach to help you.
-Also consider all checks and captures on your side and also your opponent’s side. Always as, “If I move here, where is my opponent going to move?”
I hope that this helps.
#4
"1. What fraction of my chess time should be allocated to each of the chess activities (General Studying, Tactics, Playing Games, Analysis, etc.)? In other words, if I am spending about 45mins a day on Chess, what and how should I be doing things in order to get the most out of my efforts."
A) Solve 4 tactics puzzles as a warm-up
B) Play a 15|10 time control game
C) If you lost the game, then analyse it, otherwise analyse an annotated grandmaster game
"2. How should chess software (Stockfish 14 as suggested by @NotyourCentipawn) be used at this stage?" ++ It can help you analyse
"My 30 days chess target is to skim through Soviet Chess Primer, solve 100 puzzles from the puzzle book, play and analyze 2 classical games (1 per week), and play and analyze 8 rapid games (2 games per week)." ++ Focus on one time control e.g. FIDE rapid standard 15|10. Analyse it only if you lost.

You're welcome. If you have 45 minutes per day, then 15|10 game and probably not every day, because the game itself can last for 45 minutes. Apart from that, on the day you play the game, do some tactical puzzles if you have the time.
On days you don't play games, solve puzzles as well and analyze your games. At first you will only be able to check for blunders, but after a while, you will understand more. If you have any more time, try to study something about chess. Books are surely good, but only if they are in accordance with your rating.

I knew how the pieces moves but only started playing chess regularly at close to 40. Chess was the only computer game I could play on the office computers during the hours of downtime in which I tried to look busy, minimizing my browser to some spreadsheet if supervisory walked by.
Awareness from the start that the road to real competitiveness at this game begins around age 4, not age 40--and that this ultimately condemns us to be dilettantes, not prodigies--deflated any interest on my part in making chess a serious study. Nonetheless, by continuing to play and doing a few lessons, puzzles, and analyses here and there, and watching occasional youtube videos, I still improved by about 500 points in a few years.
I confess to completely disliking books on chess since they explore games and lines in notation that is hard to follow, make sense of, and generally requires you set up the board to translate from the book. It's like trying to follow a tune by reading sheet music when you're not a musician. Learning the tactics through the online lessons, puzzles, and youtube clips is more expedient.
An important tool I didn't know about from the start is the ability to "analyze" your games after you play on this website. The chess.com computer will point out your mistakes, let you retry them like puzzles, and show you the best alternative moves. It helps you improve the lines that you play by trial and error.

1.)Look, at your and my stage of life, chess is just recreational and for fun, so I say spend it how you like. Don't treat your "chess time" like you are training to be a GM or win tournaments, don't treat it like your going to do this professionally. If you enjoy general study, do that more. Like tactics more? Do it. You enjoy the rush of playing games? Spend your time there.
2.) I don't find Stockfish to be super useful. Sure, the engine will find the best move, but it can be very hard to understand why some of the moves it suggests are ideal sometimes. Ok to blunder check after your games I suppose, and help you uncover tactics you may have missed, but I find it over my head more often than I find it helpful.

Very happy to find this thriving chess community.
I am 40, have a busy full time job, family, etc. The usual :-)
I am starting to learn chess. I've started with "Soviet Chess Primer" and a Puzzle Book. Been practicing puzzles a bit at Lichess (puzzle rating ~1900 I think, FWIW).
I enjoy recreational chess, but I think I would like to reach a certain rating in a certain time to ensure I am "making progress".
Please suggest a good set of books, software, etc. Or any other alternate path.
Thanks in advance !
Invest in some quality beginner chess books, and take the time to read them carefully. I would say this is the #1 tip. I've played for many years, and out of all the improvement I've found, chess books have been responsible for most of it.
Make sure the books are reflective of your experience level, though. Don't try to read above your level. It might be tempting to do so, but struggling with books that are too advanced for you will only slow down your progress.
Don't shy away from beginner books that are aimed at children, either. The ideas in them can still be valuable.
If you truly want to get a lot out of chess, instructive books are the key.

Very happy to find this thriving chess community.
I am 40, have a busy full time job, family, etc. The usual :-)
I am starting to learn chess. I've started with "Soviet Chess Primer" and a Puzzle Book. Been practicing puzzles a bit at Lichess (puzzle rating ~1900 I think, FWIW).
I enjoy recreational chess, but I think I would like to reach a certain rating in a certain time to ensure I am "making progress".
Please suggest a good set of books, software, etc. Or any other alternate path.
Thanks in advance !
My best advice is to “get out while you still can, save yourself!” Just remember to enjoy your pathway as you learn, and realize no matter how good you become, there is always someone better to give you a good whupping. We learn even when we lose is a good way to look at it. Go for it!

@NotYourCentipawn - That's a good idea. Thanks.
No, it isn't.
Chess engines are worthless for low-rated players. They are a useful tool for titled players (for Masters). Low rated players should be learning concepts, not memorizing lines.

Apparently already playing puzzles on Lichess and having a competent rating at them, it doesn't sound like the original poster is a complete beginner. This is someone who knows how the pieces move. I would not be so condescending as to suggest children's books.
Moreover, upon seeing the solution to a puzzle, with even beginner's understanding of how the pieces move it is almost always readily apparent why the solution was correct, but don't forget to do each day's Daily Chess Puzzle: Daily Chess Puzzles - Your Daily Chess Challenge - Chess.com These puzzles now come with the additional bonus: each puzzle has a video narration you can click (usually three or four minutes long) about the tactical ideas that were explored and why the solution was correct.

Quit now while ur ahead. Just get out while u still can. That's kind of a joke but....
We're addicts here. Chess addicts. This site is like C.A. meetings for us. That stands for Chessaholics Anonymous. We get on these forums to share our experiences of chess despair and how it's messed up our lives. The regret, turmoil, and chess sorrow. U can see it on these forums all the time, it's sad. That's why most usernames on here are aliases, because most chess players are ashamed... ashamed of what they've become. That's why we keep our addictions secret with names we hide behind like dreamscapehorizons, SmellMyFinger, and bootylicious.
Puzzles are decent for tactical ideas. Books saying why a move is made are good for helping you understand positions that don't have tactical shots (include one on ideas behind opening moves).
Once you learn about placing pieces on good squares (not calculating tactics, "merely" positional play) you will end up discovering that having pieces on good squares results in tactical shots opening up (I've lost track of how many times somebody has asked how I saw a tactical shot that was coming eight moves after a placed a piece and I responded that I did not see it but I knew the piece was being placed on a useful square in case anything happened).
Eventually you will want to learn endgames because once you know those you have a better idea of how you want to steer the middle game (or even the opening - I've made a move as early as move six because I was certain it would pay off in the endgame, and it did). For now you need to learn enough to get through the middle game so you can reach the ending (assuming it wasn't a middle game win). Once you've accomplished that you want to learn enough to reach the ending while ALSO having a decent position.

I wasn't disparaging your advice as condescending, Thechess10kp. It was another commenter who had suggested children's books, not you.
Thanks all sharing your sharing your thoughts. I am genuinely appreciative.
Putting it all in this one post instead of replying individually so as to not spam the forum.
I did start with a coach, who had in fact put me on my current path. But the coach came with subtle pressures and expectations of *having* to do things a certain way, so I stopped the coaching and went solo. I want to explore for fun, but also go deep, discover things that are new to me, and keep improving - which is a key motivating factor for me.
Lichess was fun, but I realized that I was being too competitive. My rating went down a few points, and boy I hated it, and did puzzles for ~2hrs straight to get it back up. Did someone say this is Chessaholics Anonymous, and that I should "get out while I still can". I think I know where they are coming from :-). So for now at least, no Lichess either. But OTOH, I improved very quickly. Make of it what you will.
I did consider Bobby Fischer's book and another 1-2 very basic/children's book, but these felt too basic and/or I didn't feel the pull. If the more experienced hands here think they are worth pursuing, I am open to a relook.
Based on the comments here, it appears I was more or less doing the right things. (1) Studying books (2) Working on tactics (3) Doing analysis (4) Using computers minimally and only for analysis. I will add the time control and a few other adjustments that have been suggested.
I picked Soviet Primer from a set of books suggested by the coach - others being My System, one of Polgar's books, and 1-2 books whose names I don't remember. The Primer is a bit advanced for my level, but unputdownable never the same. I am adopting the "take what you can" approach. I will work through the book taking what I can, and once I am done, I will start over. Do this a few times and see where it leads. As was pointed out in another comment, I will need an opening, middlegame and endgame repertoire to play decent chess, but to paraphrase Steve Jobs, the hope is that the dots will connect themselves eventually. I will of course at some point (soon I think) start reading on these topics also.
I am all ears for more thoughts on this. Thanks again.

Based on your reply, I would say that "My System" may be a bit too advanced (and possibly too dry) for you at this point. And children's books may be, perhaps, below your level.
Jeremy Silman's books might be to your liking, starting with "The Amateur's Mind" and later progressing to "Reassess Your Chess". They teach positional principles and ideas in a similar manner to Nimowitsch's "My System", though in a more conversational (and less scholarly) approach.
Also, Irving Chernev's instructional classic: "Logical Chess: Move by Move", which showcases 30 classical games and explains the thought process behind every move, in a conversational style. (I recommend this book to every beginner, as it's extremely instructive.)
If you enjoy that one, then Neil McDonald does a similar feat in "Chess: The Art of Logical Thinking", which showcases more modern games (within the past few decades, featuring games by players like Kasparov and Polgar), while again explaining the thoughts behind every move.
"A First Book of Morphy" is also enjoyed by many, as it walks the reader through some of Morphy's most instructive games (and Morphy's games were quite instructive, indeed).
I don't think you can go wrong in any approach, as long as you're attempting to learn. As you digest more learning materials, and see more games, you'll find your first repertoire will present itself naturally - as you'll find certain openings appealing, while others will not hold your interest.
Very happy to find this thriving chess community.
I am 40, have a busy full time job, family, etc. The usual :-)
I am starting to learn chess. I've started with "Soviet Chess Primer" and a Puzzle Book. Been practicing puzzles a bit at Lichess (puzzle rating ~1900 I think, FWIW).
I enjoy recreational chess, but I think I would like to reach a certain rating in a certain time to ensure I am "making progress".
Please suggest a good set of books, software, etc. Or any other alternate path.
Thanks in advance !