What are Resources?
To construct buildings or recruit units you need resources. You receive resources automatically from your resource production (timber camp, clay pit, iron mine). You also receive those resources when you are not logged into your account.
The amount of resources that you get depends on the size of your resource buildings. It is important to build up your warehouse to make sure that you don't lose the resources that don't fit. At the top right of your screen, you can see how many resources your warehouse can hold, and how many you currently have.
The number on the right shows how many of each resource can be stored. In this example, a maximum of 400000 of each resource can be stored. The numbers to the left show the resource amounts that are stored right now (53313 wood, 222435 clay, and 21519 iron).