CD Changer (aftermarket)

I have a 99 discovery I without a cd player. i just bought a changer and i have installed everything but i need to know the best places to conect the power wire and the "constant on" wire inside the vehicle. I would like to straight to the fuse box. The wires are 3 amp wires. i don't know a lot about electronics so i don't want to short anything out. I don't want to route the wires to the battery. I would rather go to the dash fuse box. Any suggestions. Thanks.