Use Layers, Colors, and Linetypes
Layers are like transparent overlays on which you organize and group different kinds of drawing information. The objects you create have properties including layers, colors, and linetypes. Color helps you distinguish similar elements in your drawings, and linetypes help you differentiate easily between different drafting elements, such as centerlines or hidden lines. Organizing layers and objects on layers makes it easier to manage the information in your drawings.
For more information about this topic, see “Control the Properties of Objects” in the User's Guide.