Working with layers : Changing the order of layers in an image
 
Changing the order of layers in an image
The order of layers within an image is critical to the appearance of the image. To rearrange layers in the image, you can easily change the stacking order of layers in the Layers palette. If a layer or a layer group has components, such as vector objects or grouped layers, all of the components move with the layer or layer group when its position in the stacking order is changed.
To move a layer or layer group
Edit workspace 
On the Layers palette, select the layer or layer group, and drag it to a new position in the stack.
A gray line shows the layer’s position as you drag.
When you drag a layer, the cursor changes to a hand. A cursor displaying a null symbol indicates that the selected item cannot be moved to a particular position.
You can also move a layer or layer group by choosing Layers Arrange and then choosing an option.