Normally I'm one to go "we don't need no stinking manuals" but with an appliance thats rated at 120 amps max it pays to be safe. Notice they recommend 2 guage wire at no more that 5' length. Notice the huge fuse I have in my pic (purchased at westmarine). They recommend a 150 amp fuse.
While these units are manufactured in China Xantrex is a Canadian company and has excellent manuals.
http://www.xantrex.com/web/id/837/docserve.aspx
By locating mine near the camper battery I was able to use automotive battery wires instead of having to make custom cables. I also used heavy shrink tubing near the terminals just to be extra safe.