Press the green flag to start, then click or touch Scratch cat to activate the next round with the timer… if you click see inside, you can change the time parameters for faster or slower sessions.
Credit to Marie-Noëlle Wurm for her wonderful class on Skillshare: play, break rules make art. What a great way to make discoveries and flex creativity muscles! I don’t think it’s there anymore. Thanks @Tarmelop for debugging tips.