Open the tailgate and leave down.

On the inside of the tailgate, you will see 2 torx head screws that hold in the tail light lense - Marked A and B in the provided picture.

Using the T-30 torx bit and the tool of your choice, loosen and remove both bolts. Set bolts aside in a safe place so you dont loose them.

With the 2 hex head bolts removed, gently pull the tail light housing in an outward direction. The entire housing should pop out of place.

The top socket is the tail light and brake bulb. Gently grab the back of the light socket and twist to remove the socket from the housing.

With the bulb socket now removed from the housing, gently pull the old burned bulb out of the socket in an upwards motion. In the same manner, replace with the new bulb by pushing it back into the socket until it is fully seated and sitting flush.

Replace the socket back into the tail light housing and twist it until it locks into position.

You can now replace the tail light housing back into the truck (making sure the wire harness isnt in the way) and secure it back into place by reinserting the 2 previously removed hex head bolts and tightening them back to a snug fit - no need to over-tighten.

Turn on the lights to test your new bulb. Be sure to place your foot on the brakes to ensure that it is lighting up properly. If the new bulb is a drastically different color or brightness, you may wish to replace the other side the same time.