Set a time using the arrows above and below the numbers. Then click "Set" to start the timer. While your timer is running, stop the project or close the Scratch website to test this project's best feature: when you come back to Scratch and open this project again, the project will remember your previous timer, and it will still be counting down!
Thank you @TWY_ for making a very good and nice-looking timer project. I like the style of the arrows and buttons a lot, so I borrowed your project and added the cloud variable features to remember each user's countdown.