Another Newbie Question, (Sigh) G5 how to open the Dvd Drive, Without an os

Question

Hi all as some of you will know!
I'm pretty new to PM, and osx. Not sure what keyboard buttons to press when first booting up my system,
Ok so heres the Deal bought a 2.0ghz and 2.5ghz powermac G5's from my work, No hard Drives so ive used a couple of 1Tb sata drives out of a couple of old pc's i have knocking about,
1. with no opearating system on the drives how do i get the cd tray to open is their a button or key I press at startup.
2. powered the 2.5 up and got this info (not sure what keys i hit to get this)
User abort
Apple Powermac 7,35.2.4.f1
Boot Rom built on 03/25/05 at 16:41:34
Then some other blurb about shutdown and macboot etc I typed shutdown? I take it that this is it's birthday date!
So Guys what are the short cut keys and what do I need to know.
These are my first ever macs and osx is totally alien to me! So while most of you guys will know this stuff off by heart  to me it's another world!
Bye the way luving all of this! Just like my first days with the pc! Only better
ps blasted the inside of the case's with compressed air! Man I cant believe the crap and crud that came out of them.

Answer 1

OK, one of the easiest ways and probably, in a sense, the best way if you are going to install OS fresh, is to boot into Open Firmware (which you actually did as described in your post).  You can do this intentionally by holding down the cmd-option-O-F key combination until you get to the open firmware white screen.
Then, type the following command:
eject cd <enter>
which will cause the optical drive tray to come out.  Drop the install disc into the tray.  Then type
eject cd <enter>
which will cause the tray to close.
Then, type the next three commands to initialize NVRAM and reboot the computer.
reset-nvram <enter>
set-defaults <enter>
reset-all <enter>
Then, as it does the reboot, hold down the 'C' key which will cause the machine to try to boot from the install disc.