if you just want to replace the bulb, just twist off the dust cap and replace the bulb. the housing doesnt have to be removed for that.
but if you want to remove the entire assembly, on each side of the lamp, on the back, there is a screw with a nut. remove both nuts, the screw is permanently attached to the whole assembly. once both nuts are removed, push the entire light out, towards the front of the vehicle. it should come off pretty easily. dont forget to disconnect the plugs for the fog lamp and turn signals. ive done this before and its pretty simple.