Don't know what you are trying to play, but maybe look into some Blues. It's only as complicated as you want to make it and there are several blues tracks in the GT Jam Station.

What I used to do learning was go through a song book (back then we only had books), and start with the 3-chorders. Pick a song you already know in your head. It's easier when you don't need to learn the song, just how to play it.

That's why I think Blues is so great to practice to. It's predictable which can be a real help.