Ok, i'll try, on the back of the cd player there will be 2 power wires.
If its aftermarket, the wires will be yellow and red.
Yellow is permanent power, used for the memory,
Red wire is the power wire, it connects to the ignition.
You need to splice the amp control wire into the RED wire.
If its a factory head unit, its the same procedure except you need to splice into the GREY wire.
Hope this helps.