How can I create a good study plan?

This probably isn't the sort of answer you wanted... you probably wanted an outline like ___ hours a day, or ___ pages a session, etc. but I'll give you something even better

First of all, the main focus should be on what you can learn. If you worry about what you're learning, and whether you know it well enough to apply it in a real game, then improvement will naturally follow. So the answer to number of pages or number of hours is easy... after your session is over ask yourself whether you've learned something. If you have, then it was enough.

Secondly, choose a routine that you can stick to. 1 hour a day is unglamorous, and you won't improve as quickly as some, but 1 hour a day for 10 years is a heck of a lot of hours. 10 hours a day you might burn out after just 1 week... which is not very many hours at all. So pick a routine you can look forward to, that you enjoy, so that you can continue over a long period of time.

Third, try to learn at least a little about each of the major areas. Those are: openings, tactics, strategy, and endgames. One book on each will be enough keep you busy for a long time... well, you already have a book, so I don't need to spend much time on this.

Anyway, that's the basics of studying.

Improving Your Chess - Resources for Beginners and Beyond...

https://www.chess.com/blog/RussBell/improving-your-chess-resources-for-beginners-and-beyond

Spend more time on each move. Your games are very short games, many of them less than 20 moves and you usually have about 5 to 8 minutes left on the clock.

An example

You spent 11 seconds on your last move, missing the fact that you could take the Knight AND missing your Queen was under attack. It's very difficult to improve your game when you skip the thinking part. 

I want to end on a positive note. 

This is a good move to find!