HELP!!! with p38 H&K system

i am instaling a alpine vehicle hub everything is fime but for the sound output into the headunit i am completely stuck

if anyone can help i would be sooooo grateful
the problem is i dont know how it could be setup so all the audio that is going to come out of the screen (Alpine TME-M770) it has a headphone output and also a audio left and right output.

thanks

the problem with the p38 h+k system,is
the front tweeters and 2 small front door speakers work of the head unit
the rest of the speakers work of the ampifier usually found on the subwoofer in the rear of the car,the cable from the amp then goes into the head unit,some models don,t have the amp on the subwoofer but have a dsp amp hidden behind the soundproofing behind the subwoofer,the speakers themselves are nothing like standard modern day speakers where 2 wires will operate it,these usually have on live wire from the amp the other is an earth like a car battery setup,which is why when fitting an after market stereo,either it doesn,t work (no sound) or fuzzy distorted sound.

if you want to upgrade from a h+k system to your local halfords specials,not only do you need the head unit you will need speakers and cable,buy the custom 17cm speakers they fit perfect in the original plastic holder the h+k ones are in,plus it saves cutting holes in door cards,but you will need a day to fit i all especially running the wires from the speakers to the head unit

so there is no way of doing this without riping out the HK system :/

but iv seen parrot hands free systems in the p38 and the audio comes from the oem system so i can do the same as that id say, so like every stereo has an audio interrupt cable right?
so i need to find this for when i want audio to come out the headunit it auto takes over.
i know it has one because of the parrot system so if they could get it then i can gewt it now (hopefully).
:/
is there any wiring diagrams anyone can post for me i realy need this