Hey ---, nice to talk with you yesterday! Giant email ahead!
Here's what we talked about:
All open source projects use version control tools like git for code submission. Mozilla uses two version control tools (hg and git) to track the history of code changes: hg (also called mercurial) is used for Firefox code, git is used for other supporting projects. The underlying concepts for hg and git are similar, but I think the documentation for git is much better so I suggest you focus on git first. Github is a web-based user interface for git. Locally (i.e. "on your computer"), you will interact with git using the terminal instead by entering commands. Version control is all about tracking project history so that it's easy to merge work from many different people or go back in time; it's an extra step/tool in software development on top of writing/testing your code.
To start working on any open source project, the first step is to get a copy of the source code repository (e.g. git clone). Then the programmer ch