To create a new layer or group using default
options, click the New Layer button or
New Group button in
the Layers palette.
Choose Layer > New > Layer
or choose Layer > New > Group.
Choose New Layer or New Group from the Layers palette
menu.
Alt-click (Windows) or Option-click (Mac OS)
the New Layer button or New Group button in the Layers palette to
display the New Layer dialog box and set layer options.
Ctrl-click (Windows) or Command-click (Mac OS)
the New Layer button or New Group button in the Layers palette to
add a layer below the currently selected layer.