"A First Foothold" quest discussion/question (puzzle spoilers)

For the first foothold quest, one if the objectives is to "nail down the roof plates on the raider structure near trapper's glade", from what people I've spoken to can tell, it's the church building in the "raiders refuge" area. When you get there you'll see a cellar with 4 lights above it, they correspond to 4 buttons. The first button is directly next to the cellar, the 2nd is on the opposite side, hidden in the makeshift scaffolding, and the 3rd is in the destroy building directly behind you if you're looking at the cellar doors. If anyone has located the 4th, do drop it in the comments, as we've spent roughly 20 minutes looking