This quest begins immediately after Snaring Thorstein. You’ll need to speak with Azar at her shop, located in the northwest of Dublin.
Secure Rathdown Trade Post
When you speak with Azar, she will tell you that she’s acquired land in Rathdown, which used to belong to Thorstein. It is currently overrun with bandits, but will make a good trade post. You’ll need to go there and defeat the bandits to secure the area and establish it as a trade post with the deed handed to you by Azar. You’ll find no more than a handful of bandits at Rathdown. An easy job for Eivor.
Once you’ve killed all the bandits, approach the wooden signboard at the northern side of the settlement. Interact with it and use the deed to build the trade post. You’ll then be beckoned by an Irish Man who will tell you a bit more about the trading system in Ireland. Rathdown will specialize in furs, but other trade posts will have different things to offer. In order to enhance the production of trade posts, you’ll need to loot cargo from monasteries in Ireland. Thankfully, there’s one nearby…
Raid Lambay Abbey for Trade Post Supplies
After speaking with the Irish Man at Rathdown, you’ll need to travel to the nearby Lambay Abbey to raid it for trade post supplies. You’ll find the abbey on a small island to the east, a relatively short distance by longship. When you reach the shore of the island, initiate a raid from your longship and join your crew in defeating the guards and looting the wealth. As with monasteries in England, you’ll need to have the help of a crew member to open specific wealth chests for supplies.
When you’ve looted all the supplies at Lambay Abbey, return to Rathdown and choose one of three upgrades based on your own preference. You can view these from the signboards that can be found within Rathdown. When the upgrade is complete, return to Azar at her shop in Dublin to trade the furs for rare spices. You’ll need to interact with the chest to her right to loot the furs and then speak with her to complete the trade. The quest will complete soon after.