First, pop your trunk and find the single plastic rivet on each side. A small flat-tipped screwdriver will allow you to pop the center out about 1/4".
Once the center of the rivet has been popped out, you can slide the entire rivet out of the hole.
Fold the carpet back to reveal the area behind the tail light.
Using a small tool (like a pick, or even a nail) you can lift the plastic catch inside of the zip tie.
With the catch lifted, you can pull the zip tie loose from the wiring bundle.
Then unscrew the zip tie assembly from the stud and set it aside.
Almost ready, just need to unplug the tail light. Push the tab in while you pull the plug out.
Now you can remove the four 10mm nuts. It's easiest with a deep 10mm socket, but even with an adjustable crescent wrench it is pretty easy. Now you can pull the lamp assembly off of the car.