If you want to set up your auto-trade shop in Path of Exile 2, you have to find Ange and complete the Hostile Takeover sidequest in Act 4. Thankfully, you can tackle it right after you reach Kingsmarch. Depending on your clearing speed, it might even take you less than 30 minutes to pick up the Anga quest and go unlock the new Shoreline Hideout.
If you're playing through Act 4 for the first time, here's how to do all of that. Note that you'll only need to do this once per League per account.
Where is Ange in Path of Exile 2?

Visiting Ange and taking the Hostile Takeover quest is the only way to set up your auto-trade shop in Path of Exile 2. You can only do so once you reach Kingsmarch, the port that serves as your twon hub in Act 4. Ange can be found near the Well in Kingsmarch, close to Rog's shop, and talking to her will start the sidequest.
How to finish the Hostile Takeover quest in Path of Exile 2

Before you can continue with the Hostile Takover quest after talking to Anga, make sure you've picked up the ship charter as part of the main quest. Then, go talk to Makoru to get your own ship, which will (naturally) let you travel throughout the archipelago - sort of like how you used the caravan in Act 2.
Talk to Makoru to set sail for Whakapanu Island. The monsters here are lvl 46-48, so it shouldn't be difficult if you've kept up with the monster level at the end of Act 3.
The objective in the Hostile Takeover quest is to unlock Shoreline Hideout, but the shoreline is not someplace you can directly visit by exploration. Instead, what you need to do is tend to the main quest of finding the weapon parts - which means you have to venture into Singing Caverns.
In the three times I've run the Whakupanu Island landing map, the entrance to the Singing Caverns has always been an inlet towards the north-western corner. Once in the Singing Caverns, you have to kill the boss in this limestone cave: Diamora, Song of the Deep.
How to unlock Shoreline Island Hideout

Once you've beaten Diamora, you can portal back to town to talk to Ange again. She will have a new option now that lets you travel to the Shoreline Island. If you've beaten Hideout maps in previous Path of Exile 2 Leagues, the process is the same: you have to clear all the mobs to claim this shore as your new Hideout.
The map is quite small, and should only have 1-2 Rares, so this can be done and dusted within a minute. Afterwards, you can talk to Ange to finish the quest - and she now acts as your shopkeeper to mediate your Asynchronous trades in Path of Exile 2, i.e. Instant Buyout Trades. You can drop your wares here, price them, and Ange will sell them for you even when you're offline.
Before you can do that, though, you'll need a Merchant Tab. This is a new type of Stash Tab you can buy from the Microtransaction Shop. Alternately, if you already have (non-Quad) Premium Tabs, they can be converted to Merchant Tabs in Path of Exile 2.
That's all about finding Ange and finishing the Hostile Takeover quest to unlock auto-trade in Path of Exile 2. Check out our other guides on the game:
- Scourge of the Skies boss guide
- What to do with the Shark Fin (Tribal Medicine)
- Great White One boss guide
- All Lineage Support Gems