How do you study openings?

I've always heard that newer chess players do too much opening study, so I learned a few very basic openings like the London and King's Indian and focused on tactics. I'm at the point now that my puzzles rating is far above my rapid or daily rating, and my understanding of openings is far below that of the people I'm playing against. 

To cut make this a quicker read I'll get straight to the point. I found opening trainers, is there any way to have a pre-made "repertoire"? I can't find a whole PGN download of popular openings. I then thought that I could just look up all the main lines for an opening and do it manually in the opening trainer, but many websites and youtube videos about the same openings conflict with each other, and it's a pretty tedious process. Is there a better website for opening training that will have solid lines of an opening already inserted which I can study? Is there a website where I can download the lines in form of a PGN and insert that into my opening trainer? I need someone to explain how to properly train openings, because I'm pretty helpless right now

The downside to studying openings from Database use and things like that is that you are on your own to weave through the lines and figure out which lines mesh well.

You would be better off investing in a few opening repertoire books.  What you have to figure out, first off, is what openings you want to play.  You need:

A) An opening move for White (I recommend you go with either 1.e4 or 1.d4)

B) A defense to 1.e4 as Black

C) A defense to 1.d4 as Black

Let's say you took my answers - 1.e4, French, King's Indian.

Now you need to invest in a few books.  At your level, best would be finding opening repertoire books of each.  For example:

The Fully Fledged French by Viktor Moskalenko

David Vigorito's two books on the King's Indian from 2010ish

One of the many opening repertoire books for White based on 1.e4.

This should take you a few years to study and master.  Once that is done, you should learn to expand within the openings you are going with.

So if you take mine, after having the basis for the French Defense, you can start using databases to expand your knowledge of the French.  Also other books can help too.  Sure, the lines the second book recommends may be different than the first book, but you are getting a different perspective of the opening.  I own probably over 20 books on the French, have gotten many different perspectives, and could literally play any line of it with either color.  I specifically won't play the Tarrasch or Exchange as White, but would be capable of playing them if I absolutely had to.

"Is there a better website for opening training that will have solid lines of an opening already inserted which I can study?" -- Yes.

"Is there a website where I can download the lines in form of a PGN and insert that into my opening trainer?" -- No, who would let you do that? It would be good for you, but terrible for them. /edit/ Actually, I did remember one site that lets you download high quality theory PGNs, but you need to pay for access. Not the same site as the Yes answer above....

P.S. I use books and the method outlined by ThrillerFan. /edit/ P.P.S. I'm not giving the names of these external sites because it is against chess.com's TOS. Seek and ye shall find.

I will say that number 2, the Website is two words.

Word one - the game we play on this site

Word two - If you take an author's writing, and you are putting it into book form, you are doing this!

You are rated 1200. That means you still blunder and you are still way behind in tactics. Those two areas offer far more potential for progress. If you study openings you halt your own progress: you put time and effort for no real reward.

4 stages kind of...

1 - Look at a quick guide or video on it, see if the positions look like my cup of tea. Look at some games from strong players. Look at the winrates and the theoretical evaluations.

2 - Fool around with it on a smurf account and see how easy it is to find good moves with entry level knowledge.

3 - Commit to mastery and build my own library for the opening, mapping out each variation.

4 - Play it lots and lots of times in blitz to iteratively improve my memory of the opening.

I write them down, replay it via any chess board, and further study the different variations that may be presented, also, study the variation of that opening based on what your past opponent(s) has played, this will for certain sharpen your memory as you diligently study different openings & variations. Yes indeed time consuming but no great chess player climbed the ranks without being diligent in their studies. I speak for expand the results are semi grandmaster lol ♟️🗒️✍🏾

*for example (mistype) ⬆️

I can recommend 2 ways to start studying openings. 1. Pick a champion you like. Get their self-annotated games and play thru them. Copy their openings and check&update with latest ideas when an opening goes wrong OTB. 2. Pick a few openings you like and get books with 100+ annotated GM games from the opening. Play thru them, make notes and update as necessary.  .... If you know how to continue the game after the opening, you will beat many higher rated players.