https://sciencewiki.science/wi....ki/How_to_Install_a_
Introduce your cat to the flap prior to when it's set up so they can be familiar with the size and shape. The flap should be opened and let them explore it from all angles. Make sure that the cut-out is even and square. Mark the screw holes on the door and align them with the opening of the cat flap The distance between the edges must be the same. Preparation Installing a cat flap in your home can be beneficial to the health and well-being of your pet. It allows your pet to move from the inside to the outside,