My screencast goes over the process of forking a GitHub repo and setting up that fork on your local machine.
I had originally intended to go over the entire workflow of contributing to a repo (forking + making your own changes and submitting a pull request), but three minutes goes by fast!
This is a single take — the second time I made it through the whole thing. This actually took me much longer than expected — I found it really tough to go through the entire process without major technical difficulties or errors.