Simple sub install please?

[BlackX5]

I've read through many posts and most are asking questions that do not relate or are very user specific. I just want to know if there is a "How To" for installing a sub and amp into the back of the X5. I'm looking specifically for which wires to tap for audio, power etc. I am not a stereo guru but I do have an idea of how it works as I've helped install this same box on one of my other cars.

Is there anything like this already? I don't know what DSP is, but I do not have Navigation. This seems like a very straight forward install if you know which wires to tap.

Thanks in advance.