I haven't removed an 8th gen bumper, but I can do a basic DIY on the 7th gen bumper for you; I'm not sure how much of this will apply to the 8th gen, but this should give you an idea.
1: Locate the two black plastic caps under the bottom lip of the trunk, and carefully pry the caps off. Under each cap you will find a 10mm bolt, remove them.
2: On the underside of the bumper cover you will see two black clips, with a flat head screw driver carefully pry the center tabs out and the clips should slide out.
3: There is one screw on the inside of each wheel well, remove them with a phillips head screwdriver.
4: Everything fastening the bumper cover on is now removed. Slowly work your way around the upper edge of the cover and it will pop off.