lut4rp gave me a link today. I understood git. In minutes. Miracles!
you can only really use Git if you understand how Git works. Merely memorizing which commands you should run at what times will work in the short run, but it’s only a matter of time before you get stuck or, worse, break something.
Half of the existing resources on Git, unfortunately, take just that approach: they walk you through which commands to run when, and expect that you should do fine if you just mimic those commands. The other half does go through all the concepts, but from what I have seen, they explain Git in a manner that assumes you already understand how Git works.
The docs is at http://www.eecs.harvard.edu/~cduan/technical/git/