Using your PetSafe 4 - Way Locking Cat Flap is a breeze. First, choose the right locking option according to your needs. The locked setting keeps the flap closed, the unlocked setting allows free movement, the in - only setting lets your cat come in but not go out, and the out - only setting allows your cat to go out but not return. To install, use the provided cutting template to mark the door, then cut it out. Attach the foam tape to the door frame and secure it with the screws. When using, make sure your cat is comfortable with the flap. If your cat is hesitant, you can try gently guiding it through a few times. For maintenance, regularly clean the flap with a mild detergent to keep it clear and hygienic. Check the screws and tape periodically to ensure they are tight and in good condition. This cat flap is designed for cats up to 15 pounds, so don't let heavier pets use it to avoid damage.