PolyNet comes preinstalled with a sample project. click/tap to move, hold space to dance. That's all there is to it! If anyone else is playing, you should be able to see them. if it's just you, you can open multiple windows of the game to test it yourself, if you want!
Polynet is a framework that makes online multiplayer just as easy as if Scratch had cloud lists, and it even handles players leaving/joining, too! there are comments inside the project that should help you get started with using PolyNet. just remember that in Scratch 3.0, cloud variables can't be longer than 256 characters, so the lists can't be too long, and numbers take up 50% as much space in the list as Strings (words) do. also it'll automatically round any decimals, so multiply them before sending and divide them upon receiving to keep decimal values. Thanks to @griffpatch for the specific method of storing numbers in cloud variables and general advice in his tutorials. They're still useful even for experienced Scratchers like me which is great to see! also gotta add tags since the title isn't descriptive #online #cloud #multiplayer #mobile #list