Go west before going up the stairs to find *Ration 5 x3 . Now go up the stairs and enter the building. Hide behind the crates near the door and wait for the soldier to walk away to take care of him. Move to the stairs on the west and look down to find a soldier. There’s another soldier on the southeastern part of the first floor so take him out as well. Now leave the area. The enemies are all in the same position as in the previous mission here so take 'em out, move to the southern part of the area and go west into Aldea Los Despiertos.
Be really careful in this area. Do not shoot them in the head because they have helmets and you’ll have to shoot them twice, so instead only CQC them. There are 2 soldiers in the lower middle path, which are very easy to CQC. There’s another one near the barricade to the northwest and another one to the far north near the truck.
As for items, there’s Anest x8 on the eastern side and Desert Auscam on the west side.
Now go to the orange line in your map and plant a C4 there (aim and plant). Move away, blow it and go north to the next area and finish the mission.