"The Insurgency" is the first chapter of Uncharted: The Lost Legacy.
Upon exiting the truck, you'll be situated within a dark warzone. You must find your way to the red door shown in the photograph on Chloe's phone. Make your way through the streets until you reach a checkpoint. Chloe will then be stopped.
After that brief cutscene, continue on through the streets and you'll spot the red door through a fence. Continue down the street while avoiding the truck's light. You'll spot a rat running into a crawlspace, which you must go through. Turn right to find two soldiers talking in the darkness. Crouch down behind cover and wait for one to approach your position. You'll then be prompted to perform a stealth attack. After he's down, hop over the barricade and head left into the next alleyway. Subdue the soldier standing there in the darkness, then climb underneath the board. Here, you'll spot the red door. Keep hold while the man pulls away the body from the entrance, then approach it.
Here, you'll be introduced to lock-picking. To unlock the door, you must slowly rotate the L3 button in either direction until you feel a vibration. Once all tumblers are in the up position, the door will unlock. After passing through, Chloe will receive instructions to meet on the roof. Head into the watery pit and wait for the guards to pass by. Head up the stairs, and continue until you reach the blue door.
Just ahead is a soldier with a flashlight. Take cover as soon as possible, as the room is swarming with these guys and you are currently unarmed. You must rely on your stealth moves to get past this place safely. Upon reaching the staircase, defeat the two guards by the entryway, then climb through the broken wall and run to the stairs. On the rooftop, pass through the laundry. Here a short scene of destruction plays. Turn left to find a ladder to climb. Climb up and drop down to the roof with the pink lotus.
Here you'll find yourself in a struggle against several guards. Run towards the pink lotus, where Nadine will appear and help you out. After taking down the first three guards, a couple more will join in. After they are all defeated, a cutscene plays, then you'll just have one more thing to do — take a photo of the pink lotus sign.