Where did you buy that from?

ive got a hooded litter tray, at first i left the hood off (so she knew what/where it is) and then i put it on... now i want to put the door on (as when shes kicking up the litter it just flicks out of the door) But she doesnt seem to understand what the door is or how to open it

So every morning/night i have to sweep up the area where its being kicked around