Use the arrows as shown in the top right corner. Press space to change the background color. It's probably going to get boring, just a lil' heads up. BTW, I only said lil' cuz I was lazy, but then again, I'm having to write this whole explanation about it which is taking up time anyways, and I'm just going to stop now.
I just used a simple script for the floating circle, and the background changing is easy.
