Open a new file that would have
766x620 px and
72 dpi. Paint it in this color:
3D4959.

Select now this instrument

to choose the corresponding cliché form the next table out of which we’ll create the lowest layer for the menu’s button.
Fill 0% on the layers.
Blending Options-Gradient Overlay
Gradient’s parameters:

Copy the last created layer and select
Free Transform option to make it smaller a little and place it inside the previous layer.
Fill 0% on the layers:
Blending Options-Inner Shadow