Audio Systems: Adding an amp and sub to 99 chevy tahoe, chevy tahoe, chevrolet tahoe

Question
Hi, I have a 99 chevrolet Tahoe and i wanted to add a amp and subwoofer to the factory system, how do I get the audio for the amp and which wire is the remote wire?  Thanks

Answer
you need a oem hi/low interface  or a regular hi/low interface with the remote turn on then this interface hears audio on the speaker it send 12 volts to the amplifier  if you mute the stereo the amplifier turns off
you can find them by calling this number 407-933-1065
they ship