To get started you need to install a LaTeX interpreter for you OS, set up an IDE and optionally install LaTeX extension(s). The suggested IDE is VSCode, either local or in GitHub Codespaces. NOTE: As of today, Github removes your codespace if you don't use it for a month. You knew it.
Obviously, you can do as you want, if you know how to. Otherwise stick with these instructions. :)
In the template repository page click on "Use this template" button, then "Open in a codespace".
Follow VSCode install guide.
In terminal (Ctrl+J to open it in VSCode or Codespace) write:
sudo apt update
sudo apt install texlive-full
Launch VS Code Quick Open (Ctrl+P), paste the following command, and press enter.
ext install James-Yu.latex-workshop