audio through the speakers?
Have a look to my own thread to find the drawings for the installation.
As I explained, you must use any of the empty power sources from the fuse case under the backseat. Under the central console we located 3 fuses and their input is positive (+).
Yellow 20 A Additional amplifier
Red 10 A Switch carputer on/off
Orange 5 A Switch audio relays on/off
To commute the audio signal we must use 2 paralell relays (8 pins)
All the signals from the factory radio ISO to the relays are positive, commuted by the switches located on the cover of the central console (I/O). From the relays we take the audio to the factory amplifier ISO.
However, if you don't feel confident enough to do it by yourself I recommend taking this drawings to an audio shop and they will be able to it for you.