The attached files contain two sanding blocks, one at 100mm wide and one at 115mm wide. These being common widths for rolls of sandpaper.

See the video here https://www.youtube.com/watch?v=OWS0kbTXyL8

Print instructions

I recommend printing the base in the middle of the print bed on its own to avoid warping. Then print the top and two hand screw knobs as a second print.