1. Build your market place 2. Click on your Marketplace; at the bottom half of the page you will see a column titled "BUY.". 3. Click on the tab for the resource that you wish to purchase. You will see a list of the selling prices for that resource, with the least expensive selling price at the top. If you do not see any prices, then none of that resource is currently available in your province. 4. In the white box that's on the line that has the price at which you wish to purchase (normally the top line), enter the quantity that you wish to buy. 5. Click on "Buy" on that line. 6. Wait 30 minutes for your resources to arrive.
Please note: (A) The higher the level of your market place, the more trades (both purchases and sales) you can deal with at the same time; for example, a level 5 marketplace allows you to do 5 trades at one time. (B) Each province has its own marketplace. You can buy only what's available in your province. (C) If you build your cities in different provinces, you will have access to more than one marketplace.