hey brother, you need some kind of 2 part epoxy, or jb weld to attach the female sides of the snaps onto the armor, and you dont need the outside part of this side of the snap...make sure to scuff the armor where the snap is going, and i also took a sharp hobby knife and scratched the edge of the snap that is going down on the armor...
then, you line up the armor with the snaps on it to the vest...i would get some kind of marking utensil, maybe just a pencil, and get the graphite on the edge of the snap so when you push it down onto the armor it will leave a mark to where you want the male side of the snap to be fatstened...then, you need some kind of anvil and hammering device to attach the male part of the snap to the side that goes on the inside of the vest...let me see if i can find a link to a picture of what i am talking about...