Hey,

You need to add images to it for it to visualize. You could try with some of your favorite wallpapers perhaps.

The docs on the site cover how to do it, but I'm going to work on making it more clearer.

Ah, I see. It's a little un-intuitive, to be honest, that a music visualization needs the user to supply an image. Perhaps supply a default image, or use the album art if the music file has one embedded?