1.	In the Timeline, click the Car layer.
2.	Click Insert Layer below the Timeline. The new layer appears above the Car layer and becomes the active layer.
3.	Double-click the layer name, type Background as the new name for the layer, and press Enter (Windows) or Return (Macintosh). As a best practice, always name each layer, and give the layer a meaningful name that indicates the type of content in the layer.
4.	In the Library panel (Window > Library), select the background graphic symbol and drag it to the Stage. Because the Background layer is above all layers except the Mask layer, objects on that layer appear over objects on lower layers.

Change the order of layers

Obviously, you don't want the background to cover the other objects on the Stage. Normally, the background layer is the bottom layer on the Timeline. You'll move the Background layer you just created.

1.	In the Timeline, drag the Background layer from the top position to the bottom position. All objects on the Stage now appear on top of the background.
2.	With the Background layer still selected, in the Property inspector, enter 0 in the X text box and 72 in the Y text box. Press Enter (Windows) or Return (Macintosh) to precisely position the Background layer on the Stage.