Instructions
Create a settler. Double-click on a city and click the "Build Queue." Select "Settler" from the list. Wait for the city to produce the unit.
Click on the settler and drag your mouse to the desired destination on the world map. Wait for the settler to reach the selected destination. It may take several turns.
Press "B" on your keyboard to build a new city. Alternatively, click the "Build City" command in the "Action" box.