In stalling a doggie door is pretty easy but there are a few considerations the instructions do not mention if you have a modern hollow core door.
-Template provided in kit
-Dremel or other cutting device
Use measuring tape to find and mark the center of the door with the pen.
Note: make sure you drill is level and straight
Use holes on reverse side of door to transfer template to the other side
Now, you have to be careful choosing a tool to cut the door. I used a dremel because the outer shell of the door is thin and the foam core will melt with too much heat from a circular saw or angle grinder. Also, these doors tend to be too flimsy to use devices that cut through both sides such as a reciprocating saw or jigsaw.
Even the Dremel melted the shell a bit
Cut through the shell on both sides of the door following the lines traced from your template
Afterwards, use the dremel to cut through the foam from both sides until the core pops out.
Last, insert the pet door and install as per manufacturer’s recommendations
Now Stinky can come and go as he pleases