hardwiring aftermarket Rear view mirror/back up camera

i would like to know where and which wires i should hardwire the mirror into the power supply has just a red/power black/ground and green/reverse wires. and the backup cam i know has to be hardwired to the back up lights but i don't know how to go about getting to them i just got this car and love it alot so i wish to have the system installed without damaging anything and preferably with no wires showing