How do you wire up a CD player to a 1988 ford xf?

you need to rewire the entire car with new speaker wire the rest power earth and acc is already there xfs were the last falcon to have "shaft unit" radiOS fitted so making the modern "dinn" size fit is tricky but not impossible you will need to cut a new face plate try ply wood sprayed Matt black good luck

you could just get an FM transmitter for your mp3 leave the old radio alone and save your self some greef spend your money on new speakers