You have to click on the guitar to get points! Once you have enough points, you can get different instruments to get automatic points per second. Most importantly, have fun! :D
I have used another YouTube tutorial from the Scratch team! It's "how to make a clicker game." If you want, you can make it so you can also press space instead of clicking. I don't know how to make it so you can do both... maybe somebody in the comments can show me. You can also add a background! It looks pretty boring with the white, don't you think? I think that covers everything!