You will need ruby and bundler for the site. Edit stuff in content and layouts folders.
This will live compile on every change:
$ cd _site
$ gem install bundler
$ bundle install
$ guard
You should serve it from the output folder, simplest way is with the python simple http server:
$ cd _site
$ cd output
$ python -m SimpleHTTPServer
When you're done with changes compile site:
$ cd _site
$ rake wczg:compile
This will compile the site and copy everything in the right place.
Now you can add files with git and push to github