Create a rounded button shape

Mark the shape, add a new layer and fill it with a gradient fill re to black.

Add a new layer and contract the selection with 6 pixels. (select/modify/contract). Hold down the Alt-key while using the Reqtangular Marquee tool to remove half of the selection at the bottom of the button.

Fill the selection with a gradient fill, white to tranparent. Deselect and apply the gaussian blur with radius 4.

Move the white part to the top of the button then apply inner shadow with a light red shade to the button, with the angle -45.