The watt meter just goes between your batteries and your controller. For this setup, you'll need some 10 gauge wire and some ring terminals. It doesn't cost much, though. The ring terminals are about $1.50 - $3 for a whole pack of them. You can get the wire at a department store. To crimp, them I used a pair of pliers but it's better if you have a crimp tool but you don't need to buy one if you don't want to. I got by without it. Keep in mind that this is a project so you'll have to do some stuff yourself but you have a forum here that can help you. I had never done this either and I figured it out with help on the internet. See how I wired my batteries up in that picture?