They dont say, but it's a click and drag type of mechanic.
I can scale the box down, but then what? I can't get over or under it. Am I missing something?
I jumped over it, turns out the room is larger than the tiles suggest
Yes, you're supposed to jump over it.
That seems to be an issue with my browser. I tried a different browser and the downloaded version. Those both worked.
glad to hear that.