One way to do it is to cut out a trim piece/frame with an opening that is the same size as the outside of the screen itself. File it around the inside so that it is just barely larger than the screen. Cut the headrest and remove enough foam to make room for the screen. Slide the MDF trim piece inside the headrest, and get it centered and level. Then, on the outside of the headrest, push the screen into the square of the trim piece, with the vinyl/leatherbetween the trim and the screen. If you measured/cut/filed just right, the screen will be a tight squeeze, and will stay put. I've never done it, but I know that is how some shops do it. Good luck!