Print the .stl file on your 3D printer.
My settings were:
0.3 Layer height.
20 % fill and.
Then print the .jpg file or the .eps file without changing the size (print it out as it is)
Cut out the image for the paper and cover it with adhesive transparent film, cut the holes for the cables.
Add some glue on the back to put it on top of the printed part.
Place it in the board and use the screws that came with the board to tighten the board to the printed part.
IT MAY BE EASIER IF YOU PLACE THE CABLES THROUGH THE HOLES BEFORE PLACING THE PRINTED PART ON THE BOARD.