1997 Ford Explorer installing fact. CD player in recently p

Here's a question that hopefully qualifies for an answer on here. I recently picked up a 97 Explorer XLT that has the fact. Stereo with cassette player and capacity to also handle a Cd player. This explorer came without the CD changer. I believe that I have seen that the wiring harness is somewhere in the console (in the storage chamber under the arm rest) and all I need to do is look for the harness and hook up the factory unit which I just purch along with the mounting bracket.
Another question if I may. The unit I purch. Has the magazine in place. May I assume I need power to the unit for it to eject the magazine. My manual states that radio does not need to be on to eject the mag. But once again, I assume there is always power to the unit.
Any help will be greatly appreciated.