We shall merge down now all the layers containing the orange button in a group. Then make a copy of this new made group and apply the Free Transform selection to turn it around.
Don’t forget to place it the same way it is demonstrated below.

Select the following instrument now and represent an opening of black color between the orange buttons.

Blending Options-Outer Glow

Take the same instrument to draw inside the made opening one more button.

Blending Options-Drop Shadow