回答:
At this point in the game, you are required to purchase lumber and trade the items before continuing. The only option at this point will be to complete the trading tutorial to continue.
The full steps for this tutorial can be found below. Note that you may need to switch to keyboard to go through these steps on PC.
1. Start by Pressing A (Xbox 360) | X (PS3) | Enter key (PC) to enter the Stockpile menu.
2. Next, Press Y (Xbox 360) | Triangle (PS3) | Enter key (PC) to send the convoy to the selected Merchant
3. Press A (Xbox 360) | X (PS3) | Enter key (PC) to confirm sending the Convoy
4. Press A (Xbox 360) | X (PS3)| Enter key (PC) to purchase the Oak Lumber
5. Highlight the Trading menu and press A (Xbox 360) | X (PS3)| Enter key (PC) to enter
6. Press A (Xbox 360) | X (PS3) | Enter key (PC) to select your available convoy
7. Press A (Xbox 360) | X (PS3) | Enter key (PC) to assign an item to the selected slot
8. Press A (Xbox 360) | X (PS3)| Enter key (PC) to purchase the Oak Lumber
9. Press A (Xbox 360) | X (PS3) | Enter key (PC) to select the merchant to whom the item will be sold.
10. Press Y (Xbox 360) | Triangle (PS3) | Enter key (PC) to send the Convoy to the selected Merchant
11. Press A (Xbox 360) | X (PS3) | Enter key (PC) to Confirm
The full steps for this tutorial can be found below. Note that you may need to switch to keyboard to go through these steps on PC.
1. Start by Pressing A (Xbox 360) | X (PS3) | Enter key (PC) to enter the Stockpile menu.

2. Next, Press Y (Xbox 360) | Triangle (PS3) | Enter key (PC) to send the convoy to the selected Merchant

3. Press A (Xbox 360) | X (PS3) | Enter key (PC) to confirm sending the Convoy

4. Press A (Xbox 360) | X (PS3)| Enter key (PC) to purchase the Oak Lumber

5. Highlight the Trading menu and press A (Xbox 360) | X (PS3)| Enter key (PC) to enter

6. Press A (Xbox 360) | X (PS3) | Enter key (PC) to select your available convoy

7. Press A (Xbox 360) | X (PS3) | Enter key (PC) to assign an item to the selected slot

8. Press A (Xbox 360) | X (PS3)| Enter key (PC) to purchase the Oak Lumber

9. Press A (Xbox 360) | X (PS3) | Enter key (PC) to select the merchant to whom the item will be sold.

10. Press Y (Xbox 360) | Triangle (PS3) | Enter key (PC) to send the Convoy to the selected Merchant

11. Press A (Xbox 360) | X (PS3) | Enter key (PC) to Confirm
