Assassin's Creed 4: Black Flag Walkthrough Part 22 – Sequence 4: “Nothing Is True...”

Optional Objectives:
Open 4 treasure chests
Knock out 3 assassins

Adewale will prompt you enter the Captain's quarters to look at some of the maps and ledgers found throughout the village on the hideout. Head on down into the quarters and go straight forward. Interact with the map just in front of you. This will give you access to Kenway's fleet. You have a few missions available to you. It is very easy to complete the first one available.

These missions give you additional income from the ships that are inside your fleet. You can send them on out to deal with the various traders in the world. By expending the resources inside the fleet menu, you can gain Reales that you can use. These are timed missions that will send the ships off. When the timer runs out then you will find yourself a richer man.

Within here you can also confront enemies to liberate trade routes. Never send in a Schooner as they are not outfitted for battle. Send in a brig. Follow the onscreen prompts to deal with your foes and claim a much safer trade route. After your introduction to the trade routes, exit the menu. Now you have a long sail to reach the destination Edward was given by James Kidd. You can either just sail there or find a Fast Travel point near it and use that to shave off some time. The long way has the advantage of many occasions for looting ships and gets a little more recommendation at this early stage in the game.

When you make it to the mission start, you will be given a prompt to formally start the mission. This will place Edward on a beach. Head around the rock just ahead  on the right to find the first of 4 chests you want to open for this mission. Now head over to the wall, climb up it and carefully enter the Stalking Zone.  Take a moment and be sure that Edward only has his fist equipped. If you kill any of the Assassins, you will immediately desynchronize.

Once in the Stalking Zone, you can see 2 Assassins in front of you. You can easily be in the Stalking zone and take them out without either noticing you. This will also ensure that you are most of the way toward one of the two optional objectives.

With the Assassins down then climb up the nearby mast and synchronize with the nearby viewpoint to reveal more of the island. After that just perform a leap of faith down into the water below. Keep some distance from the beach and swim out toward the far rocks. From there turn slightly to the right and head on over toward the beach beyond the atoll and the large rock ahead on the right. Head around, close to the edge of the area, and move in toward the beach finally. You will see an Assassin patrolling nearby as well as a chest. Move in close, wait for the assassin to turn around then go to him and knock him out. After that loot the chest to get the second of the 4 you are after.

Go around the corner now to the left. Duck into the Stalking Zone you find there and head to the edge of it. Watch the nearby Assassin guards and run up the next Stalking Zone above you. Now you can either using whistling to take them out or just run past them when their backs are turned. Wait for the second guard to turn their back then dash for the marker and head on up the slope.