Register with Sea Ray using your HIN# and you can download the owners and parts manuals. They detail everything on the switch pads.
Also note these are somewhat generic pads used on multiple boats and some of the buttons are not in use on all boats. Some of these may also have been put into use by a previous owner - especially the acc#s.
The one usually in question is the water pump (rectangle with squiggly lines) and this one on my boat is not used as it is controlled at the main panel in the cabin - I believe it is the same on the 320.
Side Note: treat these pads very well as they are somewhat difficult to find spares for.