If you have settled the same island as another player with whom you have a trade agreement, or if natives have settled on your island, you can use market wagons to trade with them. Each city has 1 market wagon. The market wagon is a covered wagon, which you control in exactly the same way as you would a ship. Do not confuse market wagons with the handcarts that automatically transport goods.
You can send your wagons across the island to trade your goods with the other player, or with the natives. Both individual trips and automatic trade routes can be used. See link to ch.8.4 "Automatic Trade And Transport".

The first time you want to use the market wagon, change to info mode and click either a warehouse or market place, and then the market wagon symbol. The cursor will change to a vertical double arrow. Click the place that the

wagon should go first. If you send the wagon directly to a warehouse, or market place, you can load it directly. Choose up to 3 items that are currently in demand, and load them from your warehouse, or market place, onto your wagon.
To offer these goods to the other player, or the natives, for trade, drive the wagon to one of his market places, or in the case of the natives, the chief's hut The wagon is controlled in exactly the same way as a ship. Once the wagon arrives, the right-hand side of the menu will display the trade symbol (a bag of money), instead of the usual wooden crate. Click the trade symbol to go to the trade menu. Click the arrow pointing up to "SELL" the goods by unloading them from the wagon. Click the arrow pointing down to "BUY" the goods. NOTE: It is only possible to EXCHANGE or TRADE goods with the natives See link to ch.8.6 "Trading With The Natives".
If your market wagon is already underway, and you want to find it quickly, click one of your market places and then the symbol for the market wagon, which now displays a question mark. Clicking this icon will cause the playing screen to automatically jump to that wagon.