LOL - it’s okay, I needed a laugh this morning (well, ANY morning).
And, as I said, I DID get it working but I’m not really sure how. I mean, I know how everyone said to do it and I followed that process, but why it worked with this one last download (of another C172) and not with the other three I don’t know and I don’t know if I’ll spend the time trying to figure it out.
So my advice would be to just download a few of the freebies out there, install them to your community folder (just unzip the file and put it all in the root of your community folder) and, in theory, that should be all you need to do. As I said, it worked with this last one but not with the other three I tried so there is something clearly different but even to this decades long IT manager I just don’t see what’s different.
But what I did find is the process of then altering those files to create your own livery is much tougher than it needs to be. Someone really ought to provide some sort of 3D painting process so you could just drop your plane into a program like 3D Coat or Substance Painter and use tools to paint as you would any other 3D Object. But since that doesn’t seem like anyone’s interested in doing I know I won’t. I’m satisfied with what the little changes I made look like (perhaps if I think of it I’ll post an example of my own livery - way too busy this morning to even boot up MSFS).