this is the piece that can be painted to match the body, or chrome. sometimes it has a black button on the front, sometimes it doesnt (all depending on year). under it, are the 2 license plate lights & unlock button.
you will need to remove the large trink lid finish/trim. read how here: post6599795.html
next you will need to find the 4 nuts that hold that trim piece inside the lift gate. they are small nuts, (size 11socket i think).
once the 4 nuts are off, you will need to gently push it out, and possibly squeeze the 2 white nipples that help hold it into place.
dont forget to disconnect the trunk lid black button.