It helps to have a teacher to point out specific things but when you are on your own you have to find your way. Consider listening to what you want to learn first – over and over.
That can be done with audio software by cutting a piece and saving it in a file. You can name it and state the bars involved. Loop it, and then follow the notation for the part you want to work on. Some parts are more difficult so you might end up learning one bar or even a part of a bar until you get it down.
You can play along with the music while you follow the notation. Use a metronome set to a slow speed and follow it. Increase speed as you learn the piece.
It is good to set a goal for any piece you are learning by trying to play as much as you can that is comfortable. You are the boss when it comes to that aspect of learning. If you had a teacher you would be pushed.
One concept is that your eyes tell your brain what to have your fingers do and then the fingers make the music. When your ears say that you have it, you no longer have to look at the notation. It belongs to you!
So just take some bite sized chunks and have at it. After you can play the piece, record and date it. It also helps to keep a log book with dates, and comments concerning what you are doing. When you can play through a piece it is time to consider moving on to the next piece.
Tom