This site is built using Hugo. Every time you commit changes to this repository, a Github Action is triggered, which pulls a copy of the repository to our webserver, and tells the webserver to run Hugo to update the live site. It takes around 10 seconds for this to happen; after that, your changes will be live on the internet.
If you want to dig a little deeper, you can install Hugo on your local computer with an installer
The site can then be built by running hugo in the top level directory. This will generate a public/ folder.
Inside the public/ folder, you can run an HTTP server to view the content locally (you could do this with python3 -m http.server).
All main content for this site is stored in the content/ folder, and then organized by topic. All site pages are rendered automatically from markdown files (.md extension), and creating new ones will automatically integrate them into the website according to where they are located in the file structure. For a markdown cheat-sheet, check the Markdown Guide. You might also be interested in the various features added by the Hugo Book theme that we're using.
If the site doesn't seem to be updating properly, log in to the server and try running /snap/bin/hugo manually. Then you can see Hugo's error messages (assuming Hugo is choking on something).