OverviewPlease note this could be a project for ones not handy with a saw, screw driver, ruler and pencil. If so Amazon can reach out to a handyman service in many areas that can do this type of install for you. I found the supplied instructions to be very easy to follow along with the included cutout helps a lot. . The total install time was less than 3 hours, this time included a 30 minute trip to the hardware store and 10 minute cleanup. Pet training was extremely easy, we worried about coming home to a house full of poop and pee!Great FeaturesWe picked this model due where we wanted to install it, its size and features. We were only looking for one with a closing door like this one has, along with DUAL magnet flaps to keep out unwanted critters. We were looking a RFID locking door but due to price and not finding one that was dual flaps this fell out as something we truly needed.Tools and supply’s recommendScrew driver, drill, level, saw, ruler, pencil, 2x4 depending on your wall thickness, Window/Door spray foam, extra screws.InstallationThe size you need is 17 inches high and 12.5 inches wide. In my project I wanted to know if it was going to fit between the window sill and baseboard without cutting them. The supplied instructions included a cutout that was easy to follow. These are the steps I took, Feel free to use this to determine if this a project you feel you can do yourself, if not feel free to ask questions for more clarification.1. I started from the inside due to the window as it was a very tight fit in the location we wanted to use. Use the supplied cutout to mark your hole with a pencil and level to verify before cutting with a drywall saw. Keep supplied cutout for the exterior wall as well.3. Push the insulation to both sides of the hole, the only insulation removed should be where the hole was cut.4. Make sure Doggy door fits in hole properly before adding 2x4, if not extend cuts into the drywall as needed.5. Cut 2x4 to add at drywall edge. This is used to strengthen the drywall, and add bracing to attach the door. Screw each place, notice holes for doggy door and avoid same placement.6. Use your drill and make two small holes from top most corners starting from the inside these are used to mark the exterior wall. Use these holes to line up the cutout and mark and lines on the outside.7. Verify everything is level and marked lines are easy to see. Cut hole from the exterior the installed 2x4 will also help be your guide depending of the saw you are using. Remove exterior hole cut and verify everything is square and the telescoping door fits in nicely.8. Use extra wood screws to attach exterior wall to added 2x4s, notice where screw holes are for doggy door and avoid using same placement. (Two people can help for the remaining parts but not required)9. Install Doggy door exterior side first and screw in place loose enough to verify inside piece will fit nicely. If not extend hole as needed on exterior wall.10. Attach interior doggy door but do not screw in internal side yet, move as need to make sure everything fits up nicely including interior walls of the doggy door.11. Add spray foam in gaps between doggy door and drywall and between 2x4. It is very important to use spray foam specifically for Window and Door and not expanding foam for large gaps.12. After Spray foam is in place secure interior side of the doggy door and get ready for doggy training!Dog TrainingWe have a Basenji, if you are not familiar with this bread they are extremely smart and very self-sufficient but stubborn at times. We worried about this in her training. PetSafe had us covered on this and supplied multiple methods for training your dog quickly. To our surprise our dog was using the door herself within 2 hours after install. So well in fact, that two days later when building the doggy house I couldn’t get her away from my work area!Pest AvoidanceOne thing I really like about this doggy door is the grey plastic closing door that keeps out unwanted critters out of your house, by temporarily closing the door from use. PetSafe also sells a second one if needed for interior and exterior opening. I find this to be a CRITICAL item that is lacking from many other doors in this price range ones less expensive.Additional idea’s for your project.Add a doggy on the outside to give your dog a nice place to “Dog Out” While also adding an additional level of protection from the elements. Granted my dog simply jumps on top and looks out rather than sitting on the inside but that’s also the bread!