You can select different shapes and colors for the 3 layers of animation and you can select 1 of 3 different musical "backgrounds" for which you can turn on or off the different tracks/instruments. You can also select a color for the background (there are 8 colors to choose from).
Tap the button in the lower left corner to bring up the control buttons and then I think you'll figure it out pretty quickly. And that's all there is to it, really!
The ever changing animations are random, so chances are you'll never see the exact same image twice. The animated patterns will be new every time you use the app.
I hope you'll enjoy this little piece of relaxing entertainment.