This is the model that you have everyone has been waiting for, assuming all of the following:
All you need are 3 short screws(2 might be enough). Screw the holder in and it's done.
Print it in the orientation of the STL.
And yes, I know there is another holder in the picture that holds unfolded paper. That was another holder that I designed, but I made it too thin, and it is just glued onto this one. It's so thin that it printed all wavy and messed up. Just make your own and glue it on if you really need that.
Enjoy.
The author marked this model as their own original creation.