Actually, no - you can still call me for more details, but that just makes it sound like the game is impenetrable. So, the basics:
Companies
There are three main ones to be found on every outpost: Gold Hoarders (a green tent), Order of Souls (ground floor of the only two story building) and Merchant Alliance (stall by the dock where the ship starts). You can buy missions from these: digging up treasure for the Hoarders, killing skeleton captains for the Order or catching/collecting goods to deliver for the Merchants. Each company will buy any loot you find that's connected to them, even if you just find it in the wild rather than on missions: chests and shiny trinkets to the Hoarders, skulls to the Order, crates and animals to the Merchant. Selling gets you gold, which you can use to buy more missions (and cosmetics).
Each company also has one bigger mission available: a long treasure hunt for a lost gold vault for the Hoarders, a battle against a ghost fleet for the Order or tracking down a missing merchant vessel for the Merchants. These are all fun and challenging in their own way.
There are also three other lesser companies: the Hunter's Call, which can only be found on smaller sea posts, the Sea Dogs (which only really exist in Arena, the PVP side mode they're closing down in March, so fuck knows what happens to them afterwards) and the Reaper's Bones. The latter is the PVP company in the main game, and they'll buy literally anything found lying around, collected from missions or stolen from other players. Trouble is, being a Reaper a) marks you as an arsehole looking for trouble and b) only gives you one place to cash in (the Reaper's Hideout) so you're an easy target for anyone looking to steal goodies.
Reputation
The main cut and thrust of the game. When you complete missions for companies, you earn reputation; the higher your rep, the better the missions you can buy from them which, in turn, rewards higher amounts of gold. To become a 'Pirate Legend', you need to get to Lv50 rep in three of the six companies. This gives you access to a seventh company, the Athena's Legend, which has even higher value loot.
Tall Tales
The main story of SoT, told across nine different extensive multi-part missions. Most of these have replay value because the story chapters/missions change from a selection, so you won't always be going to the same places twice. There's a Tall Tale menu buried in the Reputation section, and the icons on each tale match the icons on the ship map to show where each one starts. The first is in the tavern on any outpost, just interact with the book next to the mysterious stranger by the side of the bar.
There's also a separate five Tall Tales set for A Pirate's Life, which is the Pirates of the Carribbean content. It's decent, but leave it until you're used to the game. You access this from the shack on the beach of any outpost.
World Events
As a rule, there's always one world event going on that can be seen from almost anywhere on the seas. These are:
Skeleton Forts - a big white skull in the sky with green eyes, hanging over one of the forts. Multi-wave hoard mode with various types of skeleton enemies leading to a boss. Complete to get the fort key and claim the loot in the vault.
Fort of Fortune - as above, but it's a skull with bright orange cracks glowing. Much harder version of a fort, but with very valuable rewards. Expect to see players fighting over these.
Skeleton Fleet - a massive cloud in the sky shaped like a ship. Multi-wave naval combat in open water, ending in a battle with two skeleton galleons regardless of what ship you're sailing. Challenging, you collect the loot from the water when you've sunk the ships.
Flameheart - massive orange floating head in the sky. It's a multi-wave ghost fleet fight around one island, ending in a much stronger ghost galleon at the end. Tricky at first, but doable once you know how. Loot is good, but they're retiring him in March and he'll become the last stage of any top level ghost fleet missions from the Order instead.
Ashen Winds - a big red spinning tornado over an island. Boss battle against a very strong enemy with three waves, ultimately leading to the final part where he can summon meteors from the sky ('World's End'). Really dramatic, good fun. Loot is good.
If you're looking for good loot and quick reputation, world events are the way to go. But they're shared, so expect to encounter other players also looking for their share of the spoils (or waiting for someone to finish it before nipping in and stealing the lot). If there's no world event in sight and you're in open waters, watch out for the kraken!
Emergent Gameplay
Just sailing around is playing too. You might find flotsam (barrels and loot) just floating in the sea. You might happen across a sunken shipwreck with things inside if you're willing to explore (and not drown). There might be a skeleton captain on an island that drops a map or mission when you kill it. You might find a bottle with a mission in it, or even a rare blue coral bottle that sends you to a shrine to collect a special treasure. You might get attacked by a skeleton ship or, worse, a megalodon and need to fight your way out of the situation. Lots going on, even when you're just sailing between islands.
Commendations
There are shitloads of these, relating to all kinds of things you can do in game. As you earn them, they give you reputation depending on which company they're related to (except for Bilge Rat ones, which are just general tasks).
Seasons
Literally everything you do in the game also earns you renown. If you see a notification in the top left of the screen, that's renown being acknowledged. This ties into the levels of a season, you can earn up to lv100 to get gold, doubloons (fancy coins for more cosmetics and occasionally special missions) and cosmetic rewards. You can also buy a Plunder Pass for more rewards, but it's not worth it unless you're really into the game.
That'll do for now. I didn't even touch on emissaries because that's a side thing and I glazed over shrines, which are underwater instanced dungeons with more loot inside.
The new content starts next Thursday, when they bring in mysteries and seemingly burn Golden Sands outpost to the ground. GASP.