Go to the channels pallet: Windows>Show Channels. Make a new channel and
click on it to make it active.
Select the Radial Marquee Tool and make a small Circle on the left side of the image.
Press "X" on the keyboard. Now press the delete key. This should fill it with white.
Select the circle with the Rectangular Marquee. Hold down Alt-Ctrl-Shift
and drag a copy just to the right side of the image.
With the Rectangular Marquee, select the top and bottoms of each circle.
Press the Delete key to fill with white.
Hold down the Ctrl key and click on the channel to select the button.
Go back to Layers: Windows>Show Layers. Click on the background Layer to
activate it. Now make a new layer.
Select a color from the Swatches Pallet and fill the selection using the
Paint Bucket Tool. Now Deselect: Ctrl –D
To bevel the button, go to Layer>Effects>Bevel and Emboss.