The Golden Path is finally going to hit Pagan’s fortress and want your help, so start off by heading towards it. Note that you may (or may not) encounter enemies on the path to your objective, some of which may be Heavies. If you do, you can either ignore them or join in the fight with your fellow Golden Path to eliminate them.
When you get to the fortress, scout for some snipers on the walls before getting too close, taking them out if you happen to have your own sniper rifle. There will also be an enemy with a RPG, as well as another manning a mortar, so keep an eye out for the incoming mortar indicator. The rest of the enemies are your standard enemies you’ve been fighting so far in the game.
At the big blue door, use anything to blast it open and continue with your assault on the fortress, doing the same thing to the main gate. Now, the main portion of the mission will take place, with your main objective being to secure the courtyard. This is split into three minor objectives, to capture three specific areas, which are marked on your map as highlighted areas.
All you have to do is enter those highlighted areas, which will prompt a bar at the top of your screen to appear. Once this fills up, then you will have captured that area. Of course, a few enemies will spawn whenever you enter the specific zones, so be wary of that when you do enter them. After capturing all three spots, regroup with the Golden Path.
It seems some more enemies are on their way to try and recapture the fort, so the game directs you to use the emplaced machine gun. They will come from the front of the fort, with vehicles and a few helicopters. Luckily, they will converge onto your position, so keep an eye on your mini-map to see if any enemies manage to get close. Once the counterattack is finished, destroy the golden statue of Pagan to finish the mission.