Choose Window > Layer Comps
to display the Layer Comp palette.
Click the Create New Layer Comp button at the bottom
of the Layer Comps palette. The new comp reflects the current state
of layers in the Layers palette.
In the New Layer Comp dialog box, name the comp, add
descriptive comments, and choose options to apply to layers: Visibility,
Position, and Appearance.
Click OK. Any new comp preserves the options you chose
for the previous one, so you don’t have to make these choices again
if you want the comps to be identical.
To duplicate a comp, select a comp
in the Layer Comps palette and drag the comp to the New Comps button.