Flash layers let you arrange symbols and shapes so that they overlap each other without erasing and without interfering when you're trying to work on the stage.
To add a new layer above the existing layer, look for the Insert Layer button on the Layers panel to the left of the timeline (in the default layout). It looks like a blue plus sign and is to the far right of the menu below the layer list.
Step2
Click the button. A new layer will appear.
Step3
You can rename the layer by double-clicking its title and typing in a new name.
Step4
To move the layer below existing layers, click and drag it down past the layers that you wish to place it underneath.