• Click the coins button on the toolbar to bring up the Trade Orders screen. (It looks like the button in the picture above.)
• Materials are listed at the top of the Trade Orders screen, resources are shown in the bottom half.
• Make sure you have enough ships available to both buy and sell.
• You can find out what resources a Minor Nation sells using the "information" panel on the Diplomacy Orders screen or by investigating the terrain around the capital on the map.
• Click on a "B" to enter a buy bid on the resources sold by the Minor Nation.
• For more help, click on the question mark button.