If you are referring to the black side protectors, i recommend using contact cement to go along with the tape they use. The tape is not adequate. I lost one small piece and others have as well. The set on my wife's have had no problems. They are not hard to install, clean the surface well before installation.
If you have a dealer install, you probably could hold them liable if you lose a piece.
The orange fenders are simple to use. They have instructions with them on punching out the hole where they mount.