[stavros]

OK, going through the tutorial again, I think the difference between commits and changes are definitely the thing to focus on. Before your comments, I felt like I was building on a small foundation, because I didn't understand how commits and changes relate, and didn't have a good mental model of them.

After your comments, the entire tutorial is more solid, but still I feel like I have gaps. My feedback would be to really focus on commits vs changes and define their relationships, what affects them, etc before you go into anything else.