Augie,
1. you must have a plan that includes the FTP manager.
2. create your buttons the same size as the buttons

provides.
3. give your buttons the same name as the default buttons.
Upload your buttons into the root/themes directory
Then, at the admin panel>>sitelayout>>button themes: choose your custom "theme" (it should be there after adding it to the root/themes directory)
These instructions are not as detailed as you will find in the

manual. They should get you started.
Have fun!