What do I need to wire in an external CD changer?

[CrippsCorner]

Hi I bought one ages ago and never got round to installing it... model is Alpine CHA-1214 going into a headunit model Alpine 7893R. What do I need? Have never installed one before! Guess I'll be sticking it down in the boot somewhere. Cheers.

 

[VXR killer]

Hasnt 182 got a cd changer? My 172 had one under the passenger seat

 

[CrippsCorner]

Mine never came with one and it won't work with aftermarket headunits anyway!