How can I make one single ball to move around?

Question

Sorry about the question. Maybe it can be basic, but just knew about p5 and I ran off to my computer, watched the main tutorial on p5's official page and came out with that idea. Is there a way to erase every draw? Or is it another way to do it? I'd appreciate the help you can offer me.
https://code.sololearn.com/W9ztZ0JHXbpa/?ref=app

Answer 1

https://code.sololearn.com/WL7hAkf1gU32/?ref=app
Sorry though, my implementation is in pure Javascript