So, you want to make it easier for your cat to go outside by installing a kitty door, also known as a 'cat flap.' The installation goes pretty smoothly, it seems functional, and it looks good. Problem solved, right? Not so fast there, Mr. Handypants, first your cat has to know how to use it. Sometimes your cat just wants to send you a message, something like "yeah, I got yer cat flap right here."