To complete the SDS system and activate it, the dwellers need to make it functional. That ignores a bit of legwork. Well, a whole lot of legwork actually.
Walkthrough[]
First things first. Grab the Holotape For Rose from the desk in front of the SDS terminal.
The next two objectives can be tackled in any order. First, players need to install the upgraded motors at Scorched detectors installed alongside Route 65. Five in total, starting with the northernmost, northeast of Abbie's bunker.
Next, the player simply has to deliver the holotape to Rose, which will convince her to follow through with Abbie's plan. Afterwards, the player has to return to Abbie's bunker to complete the quest and start the final part of the chapter.