CCB stands for Circle, Curve, Brush. This means that there is a circle(more precisely curve) and a brush is spinning around it generating graphics. And that's all, that's how it works. This tool also allows you to see the transition between some settings (see the pentagram animation preset).
There's nothing more to say, because you don't really need to know "what these controls do", you just need to play with them and this tool will produce an image.
I've discovered CCB by accident, then made this to see more of these, but personally I think this tool really sucks and maybe you can produce something cool, but I only like the "Wallpaper" preset.
Tip: If you increase samples, you should decrease alpha to keep the same brightness.
Tip #2: You can control this canvas like Google Maps (scroll to zoom, drag to pan).