Getting to Know Layers
This section is a mini-refresher on layer basics. Using the Layers palette, you can rename and hide layers, change their stacking order, flip them horizontally or vertically, and even copy a layer from one image to another. You probably know how to do most of these things already, but you may glean a few tidbits here:Open the Layers palette: Press F7 on the keyboard or choose Window>Layers.
Select a layer: Click the layer in the Layers palette. Remember that a layer needs to be selected in order for you to edit it.
Rename a layer: Double-click the layer’s name, type a new name in the text box, and then press Enter/Return.
Change the stacking order: Drag a layer up or down the list in the Layers palette to a new position.
Hide or show a layer: Click the eye icon to the left of the layer in the Layers palette.
Convert the Background to a regular layer: Double-click the Background in the Layers palette, type a name in the New Layer text box, and then click OK. Or, select the Background in the Layers palette, and then choose Layer> New>Layer From Background.
Convert a regular layer to the Background: Select a layer in the Layers palette, and then choose Layer>New>Background From Layer.
Flip a layer vertically or horizontally: Select the layer in the Layer palette, and then choose Edit>Transform>Flip Vertical or Flip Horizontal.
Copy a layer from one image to another: Open both images in Photoshop, select the layer that you want to copy in the Layers palette, and then drag the layer to the image window where you want it copied. The layer automatically adds itself to the Layers palette for that image.