The DEMO version only includes 4 pages:
http://nuvosphere.io
http://nuvosphere.io/about.html
http://nuvosphere.io/register-community-short-v1.html
http://nuvosphere.io/docs-sub/index.html

It is possible to download these free files and install them on your server, so you can test how the site works.
Visit https://www.waybackmachinedownloader.com/en/buy-wayback-machine-downloader-recover/ to buy a fully functioning site.
Go back to the index page