I know how to commit, but I don't know how branches work.

Branches are way simpler than commits, so you're in good shape.

First we'll show you what a branch is, and how you can use one to make new commits. Then we'll show you how to look at the history of a branch. At this point, you'll have the bread and butter of branches down, so we can show you a handy method for saving unfinished work.