Jekill pages on GitHub: how does it work?

Jekill pages on GitHub: how does it work?

I have my gh-pages branch for my project. I am trying to create some
documentation for it. In GitHub, I read that every time I push things onto
the GitHub server, the page is actually fed through to Jakill.
I haven't installed Jakill locally. For now, I just want to use GitHub's,
and essentially act as a "user".
But... how does it actually work? I created a page .markdown, and saw that
the equivalent .html is created -- and marked up. Like this:
---
title: This will be used as the title-tag of the page head
---
Now, let's see.
# Is this working?
But... how do I find out how to actually use Jekill?
I am aware of http://jekyllrb.com/docs/ but I still can't quite figure out
what else I can do, and -- more importantly -- how to simply place a
markdown file that will be "templated" with the current template?
Thank you!