Owners manuals for boats in general are worthless unless you want basic information about "driving" a boat. They generally contain nothing about the engine, electrics, or accessories. When the boat is new, they are delivered with this general owners manual, but if the boat had a radio, it was shipped with the manual that the radio manufacturer supplied. Same for trolling motors, bilge pumps, etc. Switches on the console are self explanatory (or should be). NAV/ANC switch operates the navigation and anchor light. ACC may or may not be used even though there is a switch. It is for addition of a future accessory. If you need information about the engine then obtain an owners manual for the specific engine. You can probably order one on-line. If you intend to work on this engine yourself, then obtain a factory produced "Service" manual for your specific engine. They aren't cheap, but if it saves you from making one expensive mistake it is obviously worth it.