To switch on the fan, click on the red button. In a few seconds the red button will replace the yellow button. It means that fan is switched on. Then this button will be painted in green color. If you click on it again, the fan will start switch off. Then it will stop. You can also change the volume or switch off the sound. In future, I maybe will add the sleep timer for fan. Watch my other projects: scratch.mit.edu/users/Dradley