Trying to advance in LibGdx and examining source code

I just finished this LibGDX tutorial where we did a basic Super Mario. I have an unfinished game that I coded in regular java and I want to convert it to LibGdx and continue but is there anything you think I should do before continuing?
I thought to review and fully understand the source code of games encoded with LibGdx, if that’s a good idea, do you have a source code you recommend? Or I would appreciate for any other advice.