2000 Ford Focus wagon, rear tail light assembly, changing the turn signal bulb. (I used a Philips 3157 Long Life, comparable to the Sylvania that was in there originally.)
Once you open the rear hatch, there are two visible Philips head screws. What is not visible is a metal clip about 2/3 of the way down between those two screws, and two plastic posts on the opposite side of the assembly. Instructions elsewhere say to just keep pulling it straight out, but do not specify that the direction "straight out" is straight toward the side of the car, not straight back from the car.
Once the assembly is out, you just twist the light housing a little and then pull it straight out. The bulb pulls straight out from its housing, and the new one clips into place. You may want to take a moment now to check that the new bulb works.
The light housing has to go back on in exactly the right orientation (look at the plastic molding of the housing and line up the gaps), then twists a bit to stay in place. The entire assembly then goes back on with a bit of effort to get the clip reattached once everything is lined up correctly. Then put the screws back in.
Non-wagon versions of the Ford Focus 2000-2007 also have thumb screws for this tail light assembly which you access from inside the trunk or inside the hatch for the hatchback, but the 2000 wagon doesn't. No idea about the 2001-2007 wagon.
If you pull straight back instead of to the side, you risk breaking off one of the two pins on the far side of the assembly from the screw holes. As long as one pin remains, that seems sufficient to keep the assembly firmly attached when you put it back together.
