It is really easy.
1) Open trunk. At the opening of the trunk there is a black plastic piece with 4 screws in it. Remove those screws and the piece.
2) Under that there may or may no be some 10mm bolts. I have seen both. Remove those.
3) In the wheel well area, remove the 0-3 screws holding the bumper to the wheel well areal. Might need to jack the car up for this. I have a 90 deg. screw driver which worked well.
4) Under the bumper in the center, it will be attached to a plasic panel with 3-4 push-in connectors. These are a pain FYI. Since you don't care about your old bumper, scratching it shouldn't be a problem and make it easier. Just make sure you don't break the plastic piece it attaches to (unless the new bumper has it) and that you atleast save 2 of the push-ins (or have an auto parts store near by to get them at).
5) In the trunk again, pull back the side carpet in there there will be 3 evenly spaced bolts. they are 10mm and usually require an Open ended wrench, or a deep well. Remove them.
6) before removing the bumper, disconnect the license plate bulbs. I always forget that. Once done, pull the bumper down at the sides, then towards the rear to remove it. you need to make sure the studs clear the holes on the sides before pulling it back.
Hope that helps. I have removed and installed 6-8 of them now is this is the easiest way in my opinion.
2007 Saturn Aura XR | 1970 Chevy Blazer 4x4 | 1970 GMC 3/4 Suburban 4x4