In 2003, right click in the grey area of the toolbar and select customize.
Select Commands / Macros in the left pane.
Drag a button from the right pane to your toolbar, now right click on it to modify and assign macros.
You can only assin one macro to each custom button, so...
Once you have followed my instruction in Post #3
You have a couple of choices.
1. Add more custom buttons and assisn macros to each one
2. Assign the driver() macro, mentioned by cappafrank to the button which calls the others
3. Rather than add custom buttons, add a custom menu instead and then add the custom buttons under that new menu.