How to install mud flaps

so what else is loose
check stabilizer bushes , bumper bar bolts , grill fittings , external lights , engine mounts , loose splash pan under front, mud flaps , inner guards loose , battery fitting, bonnet latch tight , body insulators on chassis frame , rusted body panels

If it's what I think you are talking about it's like a mud flap to protect the engine, starter, oil pan.
You can just rip it off you it's a problem.

maybe this will help good luck

they come with instructions, lost them>
?
drill holes and use screws for most.
unless OEM type. that use existing parts.

That depends on the design of the mud flaps. Typically they have holes in the top for sheet metal screws. Look for any existing sheet metal screws in the fender wheel behind the wheel that match with the holes in the flaps - you can just remove those, put the mud flap up and put the screw back in if it is long enough (if the mud flap doesn't have a metal strip across the mounting edge, you'll need a large washer under the screw head to distribute stress across the material or it will crack).
If you don't have matching holes, you'll have to drill them. If you are going into steel, use a bit sized for the shank of the sheet metal screw, or just drill the screw in directly. After you get the screw in, take it out and fill the hole with rust-protecting sealant, then put the screw back in. If your mounting hole is on fiberglass or plastic, use a nut and bolt with fender washers under both the screw head and the nut. I recommend either stainless steel or cadmium plated hardware for corrosion protection; this is a harsh environment.
If you don't have a straight surface for mounting the mud flap, you may have to bend a heavy galvanized steel strap with holes in it (perhaps a pipe hanger) to make a mounting bracket. Attach one end to the vehicle as described in the previous paragraph, and attach the mud flap to it.
I would expect a new mud flap set would include the necessary hardware to adapt it to different vehicles. If you've already purchased a new set without any of this material, you can look at some of the other sets on the market for ideas on mounting brackets. The exact method you use is not critical, so long as it holds the flap without breaking anything (consider the stresses from flapping back and forth and try to envision where the greatest stresses and material fatigue would be), and is reasonably protected from corrosion.

Check the wheel wells and see if a mud flap or a splash guard is loose/broken and rubbing. Or even a bag or something could have gotten stuck in the wheel.

fitting rear flaps is a simple job depending on the kit you buy......you may find the rear window gets dirtier with flaps fitted,due to spray being finer.(citroen is the same a puegeot)

Its kind of hard to go though a step by step typing, its just alot to explain. What i would do if i were you is by the mud flaps from a land rover dealership they come with instructions!

You will have to go through your mud guards. Remove your tire, and look inside your wheel well, you will see two part mud guard, front half and back half. Just remove the 7 screws from the front half, 5 on the wheel well itself, and two on the bottom, retaining screw to the bumper, now depending on which side you're looking at anywhere from 5-7 plastic pop-its. Use a flat tip screw driver to loosen the pins up, then remove the pop-it studs. There are two on the bottom front that connect to the vehicle frame. Once this is removed, you can access your headlight assemby to replace both bulbs. Note, you will have to do this to replace your fog light bulb should it go out as well.

It is'nt difficult at all theres a couple of bolts at the top of the flaps to hold them in place just take old ones out and put new ones in whith mud flaps on.