Help Wiring 7pin plug on SCUT

I have a Deere 2210 that I am thinking about buying a receiver hitch style salt spreader for my driveway. My question is how do I wire the plug? I don't know that much about 12 volt wiring. All I need is 12volt power and the ground on the plug, I don't need brakes, signals, etc. Can I just wire right to the battery with an inline fuse? How do I know amps? Is there a fused 12volt supply somewhere in the back already with constant power? I have tapped into a line for a rear work light, but it was powered by the headlight switch. What gauge wire?

Any tips appreciated.