Hello!
Uh...wait...what was I saying?
Oh, right!
So, when you complete the game, or use a glitch to access the menu early, you will see a couple buttons.
But the one I'M talking about...
This lets you access UGIL (AKA. User generated levels)
To make a level, you can go to the level editor.
Unfortunately, you need a Discord account to publish a level. You can still use the editor without one, you just won't be able to publish your levels.
You can also download your levels as a .json file, as well as upload them to the editor.
(I'm a bit busy, so can everyone help add things?)