Look it up on the fische and order the fasteners. Those fasteners shouldn't be specific to Honda though, so any auto body supply store should have them (Honda wants a couple bucks each). They are round and they have "teeth" that bite into the posts.
Once you slide them on, be mindful that they are going to be on for good unless you surgically remove the clips VERY carefully.
I've also heard of people putting lumps of JB Weld and it working great too (easy to remove).
My opinion, not that it matters, is that those emblems that you have do not work or look right with those side covers. Maybe it's just the angle of your last picture?