This achievement is story based and should be completed during natural progression. Plan B is a main mission that chronologically occurs as below:
My First Gun
Cleaning Up the Berg
Best Minion Ever
The Road to Sanctuary
Essentially, start by speaking to Private Jessub in front of the gate who will open said gate and direct you to speak with Scooter. Enter the door just below Ned's in the NW part of Sanctuary then it will cutscene to introduce you to the founder of Catch-a-Ride. Take the Eridium from Scooter and the two power cells from the shop (one just past Scooter behind the car and the other at the top of the stairs).
Install the two cells into the hatches on the ground near the center of Sanctuary around the statue. Next, go over to the Hostel to the E and use the Eridium to buy an upgrade from Crazy Earl who will throw in a power cell as your introduction to The Black Market. Install the new third power cell in the street in front of Ned's and watch the plan come into action... or not.
Make your way N to Roland's house and talk to the guard outside to get the key and unlock the Command Center. Finally, listen to the message from Roland on the table just in front of you to turn in the quest.
The achievement should pop and you'll be rewarded with:
- Approx $22
- Approx 1187 XP
- Storage Deck Upgrade (SDU)