as i said i haven't done it, but basically you need to remove or loosen the inner fenders. i'm guessing that some of the retainers (screws) for the facia are behind the plastic inner fenders. there will also be something underneath the facia. there are also some behind the trunk lid between the brake lights. you may have to remove the plastic cover on the back of the trunk inside.
The third brake light is extremely easy to remove. It's two or three bolts if I remember correctly. As for the side markers, I just taped off my car and sprayed them. You can take them out if you want but I feel it's unnecessary.