This homepage is rendered by Jekyll and hosted on Github pages.
Posts are markdown files, and are stored in _posts. You should create a new post, which auto generates the necessary YAML header, by running:
_scripts/makepost.py 'Your post title' your-post-category
If the category is new, a stub file will be created for it in the top level directory. These stubs are used to build a category index. You will need to commit this file as well as the post file to git.
You can run jekyll serve in the top directory of the site to serve a local copy of the site & verify markdown or any edits to styling, layouts or includes at http://localhost:4000. The built artefacts will be in _site, which can be useful for debugging.
Pages are given a layout (in _layouts) which may use one or more include (from _includes). The site's CSS is in style.css