Loading into the game you find yourself in what I like to the call drinking establishment on one of the many outposts the game has. While these outposts may have different characters on them, all of them serve the same purpose, this is the place you come to get voyages and spend any cash you happen to earn. There are three voyage options in total on every outpost. Thesevyages are free when you first start, but after a while these voyages will also cost you coin to play them.
The Gold Hoarders: These guys want you to go and find them a chest on an island that you have to go and dig up. The hoarders can be found in tents like the one seen in the image below, with them certainly having a dastardly look about them. Just look out for the flag also in the image if you need an easier pointer. Walk up to them and chat and take a voyage you fancy from them and return to your ship to get going. Once getting to your ship go to the voyage table (not to be confused with the map table you silly pirates) and vote to start it off. Once you start a new voyage a map will or information sheet will unlock for you which you can view by pressing the RB button (this is the case for every voyage too). and using the right analog stick to select it. Simply press RT to give it a better look. If you have any other crew members you can also show these maps to them (even though they have their own) by using LT. These maps will show you an island which has an x marking the spot where the treasure is, simply look on the map table for an island that looks like the island and sail there to get the treasure. Upon getting to the island go to where the x on the map is and get out your shovel and dig (LB Button and down to equip your shovel, RT to dig). You will know you're digging in the right spot as a loud thud will be heard on your first attempt of digging, when the chest is fully out of the dirt pick it up and go put it on your ship and return it to any Gold hoarders at the nearest outpost to you to get your cut.
The other thing is the interaction wheel, which is great for those who don't feel like having a mic on. Pressing down on the d-pad will bring up an emote wheel which will allow you to do things like point, dance, clap and so on. Press up on the d-pad and you can put text on the screen for fellow crew mates to see. Do it while having an item in hand to get something to say about that item. Say you are carrying the chicken coop and have found a chicken that you need, simple just by having that coop in hand you should have an option to say "I have the chicken" to them so they know to come and see what you have got on the ship. It's not perfect mind you, as I have found me dropping text by mistake when having the wheel open. Shouting ahoy all the time can be a little annoying