Basically fours wire, 2 per speaker (+/-). I have it wired at the front behind the stereo at the main plug. All you need to do is identify which speakers you want to splice into, I used the 2 rear door speakers, the colors of the cables are on the stereo if you're unsure which is which.
After that, run your RCA's as usual and they plug into the box. The box also has two controls to adjust any noise interference but I also found it turns the power up too, which I'm unsure if its suppose to do that. Basically I have now maxed it on the box and tweaked the amp instead.
I'm still tweaking the whole install but the converter works as it should.
There are rca line converters for more money which can provide additional features such as remote for the amp but I have just taken a feed from the fusebox for ignition to overcome this.
If you know how to install subs/amplifiers, this will be no probs for you, its basically creating RCA ports as standard OEM units don't have one.