If you have an Apollo 425t/425e/433s workstation which is currently running HP/UX and would like to convert it to run Aegis/Domain then you will need a few items:
Plug in you Domain keyboard and turn on the machine. As the workstation attempts to find a bootable drive press the "ESC" key.
At the "Select System:" prompt enter C to get the config menu
At the "Config Control:" prompt enter 1 to select domain
At the "Config Control:" prompt enter E to execute the boot
This should result in the non-violatile boot PROM being changed to attempt to boot the Domain/Aegis from this point on.
Proceed to boot from tape or diskless from another Domain/Aegis workstation and continue the O/S load.