Mission 05: A Blank Spot There-ish
Objective: Reach the bunker island
Hack the bridge in front of Aiden to open the path.
Objective: Power up the generators to restore the bunker
Three generators will be located on the island (rough locations shown as blue circles on the map). The first one (directly ahead after crossing the bridge) has an audio log at the base of the building it is sitting on. Head to the side of the building and look for a lift Aiden can lower and use to ascend to a platform with a ladder on it. Use the two ladders to reach the roof and an enclosure housing the switch for the generator.
Head around the right side of this enclosure to spot a camera inside it. Take control of the cameras and use the access panel to open the gate. Inside are two red explosive containers. Back up and put a round through them to blow apart the fence. This allows Aiden to cross to an adjacent structure and gives him access to the power switch for the first generator. Flip it to power it up and use the nearby lift to descend back to ground level.
Next, head towards the further of the two blue spots on the map (spotting an audio log down a small alley to your left as you pass). On the edge of the blue area, Aiden will be blocked by a metal gate blocking the path. Take control of the camera above and to the right. To the right you should be able to interact with a carrier to make it lower the container it holds. This reveals a camera behind it.
Transfer to that camera and then jump to another one that is down and to the left. You should be looking directly at the lowered carrier. Raise it up to show the access panel hidden behind it. Hack the panel to open the gate and let Aiden inside.
Back in control of Aiden, enter through the now open gate and head for a stack of three shipping containers (the top of which is linked to a lifting system allowing it to move). Climb up to this movable container and activate it to be slid over to a shipping container acting as a bridge. Head through the container and into the enclosure on the other side. Flip the switch inside to activate the second generator. Head back the way you arrived to reach the ground again.
The last switch, I expect my approach is different than other guides but it does work. Head back to the canal next to the final blue spot (back towards the first generator's location). Jump down into the water and swim around until you find a large metal door you can interact with. This will open to reveal a lone motorboat. Climb inside it and take the wheel.
Motor outside and to the North-West (the direction you arrived from). Scrape along the wall here where the tires are. Stop when next to a set of these tires and climb up and onto the otherwise locked area. Enter the small enclosed area to the south to find the final generator switch.
Objective: Enter the bunker
It's time to finally reach this mysterious bunker, but first we need to get out of this area. Look for a forklift on the opposite end of this fenced off area and use it to jump the fence. Follow the objective marker to the side of a shipping container and use your phone to open it up. Step inside and after a short traveling sequence, Aiden will finally enter the bunker. Open the door and walk inside when the crate stops moving.
Objective: Search for the power controls
Clara will arrive shortly and your objective will change (yeah it doesn't complete, it just changes).
Objective: Power up the bunker
Follow the new marker to find the switch and flip it to power up the bunker. Cut-scene and the mission will end.