Fitting car mats

I picked up my new 197 today, and collected some renault sport mats.

Apologies in advance, but how do you fix the drivers mat down? It has 2 black caps at the back (towards the drivers seat).

At the moment it sometimes slides forwards?

Any help would be great!
 
Christ do 197s not have the little pop posts? without them there is velcro but it's a touch dangerous :s
 
No velco

The black caps pull apart into 2 pieces, so i was guessing one half goes under the carpet but that would involve cutting a hole in it. wasnt too sure about that
 
You need another 2 parts, squares with a spike under and a nipple on top. Spike goes through carpet, nipple engages into mat.
 
I had a set with my car, the plastic clips weren't with them, I asked the dealer, but they said they couldn't get any. Crap really. Sticky back velcro stop mine slidding around.