I just finished this job, here are steps as I remember. I only did passenger side for now. This took me about an hour this first time, could probably do it in 15 mins next time. When I have to do the drivers side I will probably remove the battery to have extra room.
1. Turn the cap counter clockwise 1/4 to 1/2 turn until you can remove it
2. Disconnect the wire connector from the cap
3. Turn ballast to disconnect it from the bulb, in pic below you can see how the bulb seats in
4. Pinch the clip tops together while move towards rear of truck, these are hinged and keep the bulb in place
5. Pull the bulb out
6. Put the new bulb in, on mine the filament pointed down to seat correctly
7. Reinstall bulb retention clips by pinching and putting back in the up position
8. Attach ballast to bulb with a clockwise turn to seat the pegs
9. Reinstall cap with clockwise turn
10. Reattach wire connector
OEM (I think) bulb:
View attachment 3305371
Ballast with new Phillips bulb attached:
View attachment 3305378
Ballast installed:
View attachment 3305379