In the toolbar you see a picture of the selected civilian along with information about him. On the map you see your two civilian units, a variety of terrain, towns, and defensive military encampments (small tents). 

There are seven types of terrain that always supply a resource: fertile hills(wool), plantations(cotton), open range(livestock), farms(grain), orchards(fruit), ranches(horses), and hardwood forest(timber).

There are two types of terrain that might conceal mineral resources: barren hills(coal or iron), and mountains (coal, iron, gold, gems).

Some of the other types of terrain on the map supply nothing of value like plains, or become valuable later in the game, like deserts.