Open 400*300 document.

Now, select the "Rounded rectangle tool"
Radius: 10 px

Right klick and make selection.

Press the "OK" button

Now you have select the area you want to fill,
Copy and paste (Ctrl + C and Ctrl + V)

Then open the "Layer Syler" and select "Grandient Overlay"

Now it should look like this.

Now make a selection to the button, (Ctrl + klick on layer)

Klick on "Select" at the upper menu, go to "Modify" then "Contract"

Contract By: 6 pixels, then "OK"

Now Copy and paste (Ctrl + C and Ctrl + V)

Open the Layer Style and select Grandient Overlay and Inner Glow

Inner Glow: