How do I wire a car stereo?

At the time of PlayTape's launch, Earl Muntz's Stereo-Pak (based on the broadcast "Fidelipac" cartridge system) was the current reigning sound delivery system, and his car players were offered with stereo sound. Bill Lear's 8-track tape system, though in production, had still not achieved its market potential. Moreover, neither Lear or Muntz was offering a portable player, though Muntz eventually did sell one.