To be honest it's not too difficult. There are loads of circuit diagrams around (especially on this forum). Take your time over the planning stage. Draw up a circuit diagram (pencil and paper is as good as anything) and a wiring list. Find few which have your components of choice then see what the differences are. Get the folks on here to comment on your thoughts and ideas. Pay close attention to cable sizes and fuse ratings. There are some pretty big currents involved with some of the cable runs so don't underestimate the size of cable and the size of cable. ANL fuses are BIG both in Rating and physically. You'll also need a hefty crimp tool, carious crimp sizes, and lots of heatshrink.
If you're not confident get a professional in, that's an auto electrician it's pretty specialist work.
