Open up a new 88 x 31 pixel image.
Use to make it the colour you want. I’m using red.
Click and copy these settings (use a different ‘Line Style’ if you like):
Choose the colour black on your colour palette (as a foreground colour), and draw around the edges of your button.
Now use brushes, tubes, whatever you like to decorate your button.
Finally, add your site name clearly and save!