To View the website, you simply need to open index.html. The JS/CSS bundle.js is included in the repo for simplicity.
Follow this link
You can also install this via HomeBrew.
If you're really confident, the best choice is to user Node Version Manager (NVM).
After Node is installed, install all dependencies of the project (Webpack, Sass, etc.)
$> npm i
Once dependencies are installed, run the build script.
$> npm run build
This will create a new /dist directory with a bundle.js that is used in index.html. The bundle.js file has all the JS and CSS files needed for index.html to run.