Gather your tools: flathead screwdriver, pencil, 1/4" drill bit and pilot hole drill bit (1/16")
Remove your old mud flap, if you have one.
We need two holes to match the mud flap. This fender already has one hole because it had a mud flap.
Your mud flap comes with two Chicago screws and leather washers. Decide where you want it to go, with the narrowed end of the flap hiding behind the fender and undo the screws. Now grab your pencil.
Line up the existing hole, if you have one, with the first hole in the mud flap.
Flip over the fender and make a pencil mark where the second hole needs to go. If you don't have one hole already, make marks for both holes.
Use your pilot-hole drill bit to drill a hole where the pencil mark is.
Darn, the pilot hole was off-center. That's why we drill a pilot hole! If necessary, drill a second pilot hole that is centered above the first, bottom hole.
Switch to the 1/4" drill bit and drill a hole where the (centered) pilot hole is.
Now you have two 1/4" holes to match your mud flap holes.
Line up the holes in the mud flap and the fender with the mud flap behind the fender.
Put the leather washer and the smooth side of the Chicago screw on the outside of the fender.
On the flip side of the fender, install the flathead side of the Chicago screw with just enough twists using your hands to stay in place. We'll use a screwdriver to tighten it down.
Install the second leather washer and Chicago screw.
Use the flathead screwdriver to tighten down the screws on the backside.
Voila, your mud flaps are installed and ready to repel the rain. Go for a ride!