Which type you have? Pre-facelift or facelift? If you need to see photos and understand how they stand on the bumper look-->Here
I have facelift and around the foglight there is a black plastic part like a base. There is possible for keeping the fog stand properly into the bumper. You must know, that they are a bit loose, so when you fall into bad road they can move a little like a dumper.
You need 2 small clips being put into the bumper to hold the fog lights. No matter where you bought the stuff, they should have either told you that the "kit" is incomplete or send you the clips. Email me I will help you out buddy.