it's wonderful to be able to give your cats access to the outdoors, where certain you and your cat, can conveniently enjoy the freedom and independence with the Stay-well Big Cat Door. The door is great for large cats and small dogs weighing less then 25 pounds and can be installed in an interior or exterior door. This video is designed to walk you through how to install the Stay-well Big Cat Door and some important tips on how to make your installation go smoothly. The big cat door can be installed in wooden, pvc, metal or glass doors or glass windows. Do not install this pet door in glass, without consulting a professional glazer. The tools will need to install your pet door, may vary, depending on the material of your door. more basic installation will require the following tools. A tape measure, a drill and a half-inch drill bit. An appropriate cutting device such as a Jig Saw. scissors, tape, sand paper and a pencil. An more advanced installation may require a few DIY skills. Once you have chosen the location of your door, you will need to determine the height of the door based on the height of the cat. Now measure from the bottom of the door to the belly height of your cat and mark it. Bear in mind, that this mark will represent the bottom of your pet door when it is installed. Remove the door from it's hinges. Place the door on an appropriate cutting surface, we recommend Saw Horses. You should also note the top and bottom of your door. Find the center of the door. Note the height line that you marked earlier. Do not install your pet door less than three inches from the bottom of your door, otherwise you will compromise the structural integrity of your door. Once you are comfortable of the chosen location of your pet door, tape your template into place. Using a half inch drill bit, drill a hole, just inside the circle template. Using an appropriate cutting device, cut just inside the template line. Now your ready to begin assembling you Big Cat Door. Now you will need to install the core door covers of your pet door. Begin by measuring the thickness of your door. Take the thickness of your door and subtract 5/16 of an inch. Take this total and use it to measure your core cover pieces, and cut them to size. Insert the uncut edge of your core cover pieces into the tunnel frame. Tape the corners of your core covers into place. This will help ensure that the core cover pieces do not pop out of the tunnel frame. Now install the other side of your tunnel frame. Now take this section of your tunnel and place it in one section of your pet door frame, and tape it into place. Take this section of your pet door and install it in the underside of your house door. It may help to tape it into place, but be sure not to tape cover the screw holes in the pet door. It may also be helpful to lock your pet door flap as your doing the next section of your installation. Now install the interior frame of your pet door. Ensure all the holes in your pet door are aligned, and using the screws and nuts provided, install the screws and secure the door. Be sure not to over-tighten the screws. The screws may be longer then the depth of your door and may require trimming. Mark the excess length of the screw, unscrew one screw at a time and trim them and reinstall them. Use the plugs provided to cover the screw holes. You are now ready to begin acclimating your cat to your Big Cat Door. This door features a four-way locking system. It offers, In-only access, which allows your pet to go in, but not out. Out-only, allowing your pet to go out, but not come in. Open, which offers full access, and locked. It may take a little time for your cat to become comfortable using your big cat door. It may help to tape the flap of the door out of the way, for your cat in the early days of using it. it is a good idea to not to use the four way lock until your cat is throughly familiar using the door. Once your cat has had a bit of time to get used to using your Big Cat Door, we're certain you will both enjoy the freedom and independence that a pet door provides..