Click the flag. Yoshi will start to change colors. Then use the right, left, up, and down key to move right, left, up, and down. Some beats/sounds will come up and some point according to when you hit the right, left, up, and down keys. The sounds will not come immediately you will have to wait for them, so don't get worried that I messed up. Oh, and a Kylo Ren will pop up and some point. Another thing, the cat has a pen and you will make lines as you move.
How did I make it? Well, I just did what I always do, make a cat that can move with some sounds and a color changing Yoshi. What more is there?