In order to run this app you will need a simple web server running to serve the files.
I like the one below.
https://www.npmjs.com/package/local-web-server
If using terminal, run the web server in the same directory as index.html by typing ws, and you should be able to view the app at localhost:8000.
This was built to be a mobile app. It is styled for that purpose only.
It will look too spacey on a desktop sized browser.