PuffinCat is becoming increasingly feisty and we'd love for her to be able to come and go as she wants and stop shredding our feet. We have a garden and cat flap. However. PuffinCat is not particularly blessed in the brains department and can't seem to figure out the cat flap (this is a cat who regularly struggles to find her way out of the litter tray). How do we teach her how it works?