1. Visit DanceSpots.com on your mobile device
2. Tap the browser menu: 
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   •
   •
   on Android or
   ↑
   on iOS
3. Tap 'Add to Home screen' in most browsers, or in FireFox tap 'Page' then 'Add Page Shortcut'

There may be additional confirmation steps.

Video tutorial of this operation: https://www.youtube.com/watch?v=cGWWNjDX8ho