https://elearnportal.science/w....iki/Using_uPVC_Cat_F
It might seem daunting to set up the flap for your cat however, with the proper guidelines, it's not all that difficult. First, determine the height you want the cat flap to be (on average, belly height). Mark this point on the door, and use the template provided as a reference to drill. If you have a small kitten, prop the door open a bit and gradually encourage it to pass through. Reward the kitten as it passes. Take a measurement of the door A cat flap allows your pet to go in and out of your home at its convenience.