To affect all the layers below the adjustment
layer, click the Create Adjustment Layer button at
the top of the Layers palette, and choose one of the following adjustment
types. (The first three options in the menu are fill layers, not
adjustment layers.)
To affect only one layer or several successive layers below the adjustment layer, choose Layer > New Adjustment Layer > [adjustment type] . In the New Layer dialog box, select Group With Previous Layer, and then click OK.
If you selected Group With Previous Layer in step 3, Photoshop Elements groups the adjustment layer with the layer immediately below it and the effect is confined to the group.