Press space or use the arrow keys to change slides. Fullscreen is recommended. You can remix this project if you want, but I recommend recreating the code yourself to help understand how it works. Here's a visual representation of the collision physics: https://scratch.mit.edu/projects/224258626/
I previously made a tutorial that explains how Rolling on Slopes works, but it was a bit more complicated than it needed to be and didn't provide any information on how to code it. So, here's a simpler, code-based tutorial! :) Please include a link to this project if you plan on remixing it or making your own so that people can see how this works themselves.