The DEMO version only includes 4 pages:
http://skribbleio.com
http://skribbleio.com/skribbl-io_ext_iframe.html
http://skribbleio.com/privacy-policy.html
http://skribbleio.com/terms-of-services.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