Not really a guide(its pretty self explanatory), but just a caution
This achievement glitched for me and did not unlock on my first playthrough. The tracker said it was at 100%, but I got nothing. I had to playthrough the entire thing again, and the achievement unlocked at the beginning of the final cutscene. I have not seen anyone else say this happened to them, but thought I would let people know. Good news is that the entire dlc can be beaten in about 30 minutes if you don't care about collectibles and what not.