Are the clips on your car now? If so, and if they are in good condition, then put the bolt on the front end of the molding in the hole in the fender and loosely tighten it. Then carefully place the molding on the upper lip of each clip and snap it down over the lower lip. Sometimes it goes on very easily, and other times..... I usually just use the heel of my hand to encourage the difficult ones. Also, I sometimes find it easier to skip every other one to get it in place and then go back to the skipped ones.
Once you have the molding in place securely on all the clips, go back and tighten the nut on the front bolt.
"I love it when a plan comes together!" -- Hannibal Smith
Murphy, 1968 Coupe - Concours
Trouble, 1968 Fastback - Modified
Moby, 1971 Mach I - Occasional Driver
MiniMe, 1966 Mustang Jr. - For Fun
MCA Gold Card Judge, 67-68 Concours
MCA Gold Card Judge, Modified