Using several layers in Flash allows you to create a complex scene and have more control over your artwork. If you have been drawing in Merge mode rather than Object mode (cf. Chapter 3), you need to put graphic elements that you want to keep separate on individual layers so they do not merge with the shape underneath.
By default there is one layer in your Timeline. To create a new layer: Insert > Timeline > Layer or more simply click on the add layer icon.
Each layer has its own color. This is seen when viewing ...