Trading
From Against the Storm Official Wiki
Once you build a Trading Post, Traders will visit you periodically. You can barter with them by selecting their goods and offering some of your resources in return. The bar beneath the selected goods will show you if the Trader is happy with your proposal, and once the bar turns green, you can press the "trade" button to confirm the transaction.
When there’s no Trader in town, you can select the Trading Post and find out when the next one arrives. Traders will not come during the Storm. Traders can also be attacked and robbed. To do so, use the sword icon in the Trade Panel. But beware, this action will have severe consequences.