This is a diagram illustrating Git, not GitHub. Git is a version control system. GitHub is a hosting platform for Git repositories that adds a web interface and social features.

I learnt how to use Git by picking up the basics, then whenever I needed to do anything new or whenever something didn’t make sense, I read about how that part of Git worked. Also, I read the Pro Git book, which is free and linked to from the Git homepage. If all you ever do is look for a quick fix or use a cheat sheet when something doesn’t make sense, you’re the “One year of experience ten times” developer, so try not to do that.

Learning how GitHub works after you understand Git is easy.