cd changer installation

i'm trying to install a 10 disc cd changer into my 96 buick regal. everything is ready, except for 2 wires connected to the changer. the changer is a sony cdx-565mxrf if that helps. anyway, there is one yellow and one red wire that need to be connected to one of the many wires in the regal's radio. i have no idea what to do! please help!