Paul is trying to destroy the Statues of Kyra and Amita wants you to stop him. Make your way to the site of the statues and you should be in front of a gate, where you could either blast through it or find another way inside. If you go below, you’ll find a series of grappling points that will allow you to sneak inside the compound.
Blasting your way inside will alert the enemies and start a five minute timer, while sneaking inside won’t do that right away. As you make your way to the detonator, the timer will automatically start, whether or not you were detected. Now, you can try and sneakour way up as far as you can, but considering the timer, it’s best to just start blasting your way up to the detonator.
The only enemy you want to really be careful about is the sniper located near the detonator, so if possible, try and take him out first. When all enemies are dead or you have little time left, neutralize the detonator to begin the second part of the mission. Pick up the sniper rifle, as it will come in handy shortly, and get ready for more enemies.
They will be coming from the bottom, where you started and they won’t know you’re there until you start shooting at them. Depending on the weapon you have (should be an assault rifle or LMG at this point), start gunning down the enemies as they climb towards your position. Enemies can get to you from either side, as well as a ladder next to the ammo refill box.
There will be two thing to watch out for as the enemy waves come up for you, with the first one being a sniper off to your left. If you see your health drop a lot, then there’s a good chance it’s the sniper. The other thing is a helicopter that will attack you. If you have a RPG or the grenade launcher sidearm, then use them or you’ll have to try and shoot the pilot with the sniper you grabbed earlier.
Once all enemies are dead and the helicopter has been downed, there will be one more thing to do, with the objective being different depending on who you sided with. If you are with Amita, you have to block the road somehow. There’s a path you can get to, with some enemies below (two are snipers) that leads to a grapple point. Use this to get to a point where you can shoot the area below a giant rock that explodes and dislodges it (pictured above).
Siding with Sabal will grant a different final objective. He will want you to light the two braziers on the remaining statue’s hands. Make sure you watch out for the enemies below, as a few more will spawn. There will be grapple points and ladders that lead to the hands, which you simply need to interact with to light them.