First put it on fullscreen and then turn the sound up. Click the dot you want and click play to here it. Click the reset button to clear your rhythm and make the line go to the start. You can click play and pause. The up arrow makes the rhythm go faster and the down arrow makes it go slower. Hope you like it! Hold space to see speed.
Credits to @djpro for the text engine. I kinda just got the idea when I saw a friend do a rhythm game so I thought I should try and make one.