The published website ends up here:
https://stanfordaha.github.io/aha_tutorial/

This website is using the Jekyll-Github Pages described here:
https://docs.github.com/en/pages/setting-up-a-github-pages-site-with-jekyll.

To run this locally you need to ruby, jekyll, etc. as described in the docs.

To view the website locally:

bundle exec jekyll serve --baseurl ""

and view localhost:4000 on your browser

Please verify it works locally before creating a PR.