Remove the tail light assembly. Open the rear door, and look at the side of the light assembly. You will see two openings for the screws. These are TORX screws, can't remember the size, but I have a torx screwdriver with multiple tips that store in the handle. I think it cost about $5 at Ace. It's got a tip that fits. Anyway, remove these two screws and the assembly can be pulled free. It has two guide posts that pop out of guides in the body. You have to line them up on reinstallation. With the assembly in your hand, flip it over and remove the bulb assembly from the reflector body. There are four clips that hold the bulb assembly in place. Once free, remove and replace the bad bulb and put it all back together.
It's pretty straight forward,you have to remove the taillight from the body of the car and then remove the connector plate at the back of the taillight that holds the bulbs. I've included a video shows how to accomplish this and also how to replace that connector plate if you need to.