Fork and clone the repo locally then...
git submodule update --init --recursive
gem install bundler
bundle install
bundle exec jekyll serve -wIoFiles contained in the _pages directory will be rendered as HTML pages. Two files should always be in there: index.md and slides.html.
index.md will be what is shown to anyone who goes to the main url.
slides.html creates the slides using the _slides directory.
Add markdown files in 000 to 999 order inside the _slides directory. The 999-reference directory is for reference only and should be deleted before site is published.