This is built with elm. You'll need to install the elm toolchain to build it.
https://guide.elm-lang.org/install.html
Then you can just use make to build the site.
The genlink script will generate a link and a URL query string you can
use with the web app to pass in a challenge message.
If hosting online, once the site has been built, only the contents of
the site directory need to be uploaded.