I've put together a lot of cheap furniture that comes with a million pieces and dubious instructions. I am patient and have never given up on an item before. This pet door, however, was the most frustrating assembly I've encountered. For one thing, the instructions are tiny, for elves. The pieces are bulky and not identified (such as part A or Part D x4 etc)
Once I got it together and tried to install it in my doorway, again frustration. No matter how I positioned it or readjusted the 4 screws/ brackets, it was not secure. My door is pretty straight, not wonky or anything like that. I just decided to call it quits and return it.
A couple of other points - I got this mainly to keep cats contained, but there are large gaps (between the metal) on the sides that my slender kitties could get through. It would've kept my chonker out, which was the main reason I wanted it, but FYI if you're trying to separate skinny cats. Ha.
Also, once you put the pin in the door, you have crossed the Rubicon. The instructions tell you this - once in, it cannot be removed manually. I mention this because it won't fit back in the box with this piece assembled, and made the return process for this bulky item annoying.
But, Wmart was great with the return at least.
Good luck!