Wiring accessories to the system.
Connecting accessories to the system is easy - in the power box there are two screw terminals (clearly marked for 12v and ground) for each circuit so connecting something is requires inserting the wires for that accessory in the terminals for the circuit you want to use and tightening the screw terminals.
Connecting them is easy, but the instructions are a bit unclear about the current capacity of the system and each circuit, so here's a little more explanation.
The system is advertised to have a total current capacity of 60 amps, but out of the box the 8 circuits are fused for 30, 30, 20, 20, 10, 10, 5 and 5, going from circuit/switch 1 to circuit 8. The instructions say that circuits 1 and 2 are capable of handling 30 amps and circuits 3-8 are capabile of handling 20 amps. No matter how you add up those two sets of numbers, the total is more than 60 amps. Also, the supplied circuit breaker is 100 amp, so why is that when the maximum capacity of the system is 60 amps?
The maximum surge current of the system is 100 amps, so the circuit breaker protects against that. Surges can happen if multiple accessories were turned on at once, or if the motor of a motor-powered accessory stalled, or in other ways, so if a surge over 100 amps should happen, the breaker will pop to protect the system. That's the first level of protection.
The second level of protection is the fuses for each circuit. As per the specs, the 30 amp fuses provided for circuits 1 and 2 protect the maximum current for those circuits, and the 20 amp or less fuses for circuits 3-8 protect each of those at 20 amps or less.
The third level of protection is for thermal overload - assume the accessories currently turned on draw over 60 amps in total, what will happen is when the electronics in the device reaches a certain temperature the thermal protection will trigger and shut the system down until the electronics cool.
With these 3 levels of protection it should be impossible to damage the device through overload or short circuits.
But since it is possible to connect a bunch of accessories to the system that could draw more than 60 amps in total, a little planning is necessary. Add up the total current draw specified for each of the accessories you plan to connect to see if the total for your use of the accessories would exceed 60 amps. I say "your use" because if there are several high current accessories you would never use at the same time, you can connect them all even though turning them all on at the same time would exceed the maximum system current. So when doing your math, account for things that will never be turned on at the same time.
If you have accessories that require more than 20 amps but less than 30, those must be connected to circuits 1 or 2. Anything that requires less than 20 amps can be connected to circuits 3-8. And if you have an accessory that requires more than 30 amps, or if you plan to simultaneously use multiple accessories that in total would draw more than 60 amps, some of those high-powered accessories should be powered by a relay driven by one of the circuits.
Here's how a relay would be added for a high-current accessory:
The accessory also needs to be grounded, that connection isn't shown in this drawing.