So the mud flaps do not have mounting holes already in them. the way my bumpers are there is a 3/16-1/4" gap that the mud flaps go into. I held the mud flaps in place and marked the holes. I then removed the mud flaps and punched holes using a punch set I got from Harbor Freight. I then installed the mud flaps and used some fender washers to make a tight fit. We did Zelda the same way. Hope this helps.
Steve A.