All files are in the gh_pages branch. Select using the dropdown above:
The site uses a modified version of the jekyll minimal theme.
The pages are visible at https://uclcomputerscience.github.io/pgta/
Edit the markdown files in the root.
When you commit the change a GitHub Actions workflow runs that updates the web pages.
Create the text content for the page in a markdown file and save it in the root.
To add it to the sidebar menu then edit /_includes/sidebar.html and follow the syntax.
As above, commit the change which will trigger the workflow to update the site.