I got this backrest as a present last year and finally got around to putting it on the seat. Wasn't the easiest install I ever did, and I did look at videos online to see what was needed.
This is the backrest that is sold by big bike parts. It is not the quick remove version, although if the parts are cheap enough, I may get them and convert it. Most of the instructions are easy enough to follow, but where I had some problems was after I cut the top of the seat and put the connecting bar inside. I couldn't get it to go in far enough or get the holes close enough that I could screw the bolts in from the bottom. What I should have done is attach the top part of the mount to this bracket and that would have made it much longer and easier to maneuver. Like most projects, you eventually figure out how to make it work.
And when it was all put together, I tried to raise the seat up on the gas support only to find out I somehow got the bolts in the back tightened up without going through the hinges themselves. And that was after I got it put together without the bushings in the hinges. Live and learn.