The third copy:

Blending Options-Gradient Overlay

Gradient’s parameters:

Take now a new instrument and represent the button painted in white.

Using the same instrument and keeping pressed the Alt button, it’s possible to erase the upper part of the button.

Copy this new made layer three times and place everything the same way it is shown below.

Take the photo with the demonstrated sizes next step and place it exactly the same way it is indicated next picture.