How to change a 2001 ford focus zx2 brake light?

My brake light is out, and I am attempting to access my brake light assembly to change the bulb, and I just can't seem to get completely to it so I can. Any one have any experience with it?How to change a 2001 ford focus zx2 brake light?Take to any auto zone and they will show you. Usually go in from the back side.