Watch this video in context on the Unity learning pages here: http://unity3d.com/learn/tutorials/modules/beginner/navigation/navmesh-baking
Navigation requires the use of a simplified geometrical plane, often called a navmesh. The navmesh enables characters to plot a path around the various complex items in a scene. In this video we will look at how to create a navmesh (often called "baking") using Unity's Navigation view.