It looks to me like some of the clip-holes broke or cracked. If this were my project, I would gently sand and clean the cracks, and then JB-Weld Plastic Epoxy them. That is what I would personally use, and have had my good experience with versus other methods like regular JB-Weld, other plastic "bonding" agents, and of course, superglue (CA Glue.)
After that, I would get new trim clip pins that match the ones you have to begin with. They are old, they are going to begin to get brittle, and will only get worse with age. You can get them at a local auto parts store.
If you believe your clips/pins are fine and healthy, then just reuse them.
Next I would inspect the holes where they go into, make sure there are not clip/pin pieces stuck within that will block your re-insertion of them. Make sure they are also not damaged if any are not metal and are actually also plastic or some other material like fiberglass.
Then, if the trim piece is long and flexible which it seems like it is, press them in starting at one end, but not all the way per pin. Put it in just a bit so it's "in there" but not "all the way in." Do each pin and then when you get them all centered and properly aligned, push them in all the way. This avoids breaking them or making them bend and never go in right ever again (ask me how I know.. lol....)
You can of course just ugga-dugga them straight in one at a time, like I totally have done with mixed results. If you wanna do it right and minimize risk of having to go buy more pins/clips, then follow aforementioned instructions on how to line them up gently and precisely.
I hope that was helpful!
