There's a number of different ways to wire it, they mainly depend on how you want to separate (or join) the batteries.
I have an 140 amp battery isolator which is connected to the alternator and then splits the charge between the 2 batteries but ensures they don't drain each other.
The national luna kit has a nice manual which walks you through the different types of connections and will give you an idea how to get started:
http://www.nationalluna.com/Datashee...e%20manual.pdf
