Now that's really easy: take of the small(!) plastic cover in the trunk, the one just behind the tail lights. Use a soft tool not scratch the plastic cover. You will see the back side of the tail lights. There are two 10mm screws attaching the tail light to the body. Take a wrench and insert it into the opening. You have to be patient since there is not much space and the wrench has little room to move and has to be attached and re-attached multiple times. The screws have an extension and are longer than normal ones so that the nut cannot fall off and get lost in the body. Take off the cable connector and you are ready to pull of the tail light. Put the new one on and connect the cable and tighten the screws.
