This quest is unlocked after completing the "Overrun And Outnumbered" quest. To start it, return to Nassau and sit at a table in the local tavern.
Hearing that the Templar Torres plans to pick up a large shipment of gold from a nearby fort, Edward and Adéwalé decide to attack.
Capturing a fort, even a relatively easy one, isn't trivial, so before you set out, take some time to prepare properly - repair your ship, make all available upgrades, and only then return to your ship and take the wheel.
The fort in Punta Gaurico is guarded by a few ships - one brig and two cutters. Deal with them first, because even if you disable the fort's defenses, you won't be able to dock until you take them out. Watch out for the fort's fire at all times; large orange spots on the water indicate where it will hit. You can board the brig, which will allow you to repair your ship during this battle.
Next, focus on the fort's defenses. Your priority - as throughout the entire battle - should primarily be to avoid getting sunk. Mortar is an effective weapon here, but of course, whenever possible, use other types of fire as well - like Heavy Shots.
To disable this fort - allowing you to launch a land assault - you must destroy two fortifications.
Sail up to the fort's dock and moor your ship. Then go ashore and run up the ramp into the fort alongside your crew. A fight against the soldiers inside the fort will begin.
The battle inside the fort works on the same principles as a boarding action. The fort has a morale bar that drops with each killed soldier. To win, you must reduce it to zero. Swords, pistols, or explosive barrels - use the arsenal at your disposal effectively.
When the fort's morale bar drops to zero and its remaining defenders surrender, head to the very top of the fort until you reach the large, wooden doors leading to the war room, and step inside.
A cutscene will trigger - a conversation with Grand Master Torres, who is inside.
After the cutscene, return to the deck of the Jackdaw and enter the captain's cabin.
From now on, you can manage Kenway's Fleet not only from your residence, but also from inside the captain's cabin on the Jackdaw. This quest will end, and the next main quest will be unlocked - Traveling Salesman.
