You will need to install Elm, which is the language the main site is written in.
For the development tools, you will need to install node. Node comes with npm, a package manager that can install dependencies the project.
With the prerequisites installed, run:
npm run devThen navigate your browser to http://localhost:9090/, and the site should be there.
Edit the file in src/Home.elm, and refresh the page to see changes.
To build for production, run:
npm run buildThe built site will be available under the root folder.
This is a static site. It is built once, when something changes, and the resulting index.html served from a server.
The site is automatically deployed with Netlify.