Pretty straight forward. This is the wiring from a Ranger with a 36V system but the same applies to the switch you have. Make sure you pay attention to the notes concerning which posts to use on the backup battery connections.
Thanks Imbatman, I believe with the diagram you posted I will be able to figured out my set up of this Perko main power switch. In my set my TM is on a separate circuit that's not on in the existing main power switch. I unplug the TM from power when not using. Only items I'll have on this Perko Main power switch I plan to install will be all the Boat Switches(horn, port/strd auto livewell aerators, port/strd livewell fill pumps, bilge pump, nav/anc lights, and Ign switch) and the starter system for my Mercury Outboard. Thanks Sir for your assistance now is to acquire correct gauge and length of wire to make the connections needed. Then there is also deciding where to place this newly installed switch.