To mute, press m, to unmute, press u. (When you are choosing your character and you're not on mobile, DON'T let the mouse pointer touch the character till you finish choosing! If you do, you can't choose any more.) I know it has only few lessons but I am so busy with schoolwork and stuff like that I don't have time to add more.
Costumes and backdrops by both Scratch and me. Coding by me. Music and sounds by Scratch. I got the idea from this project. https://scratch.mit.edu/projects/200366205/