Hi BA772

I don't think is needed. You probably just didn't see that the whole IRS panel is switched off. The IRS panel is needed for the autopilot. Otherwise nothing will happen. You only have to set all lower switches to NAV. You then wait until you get a few digits on the little screen, that is your heading, if your heading know is selected in the IRS panel.
I had it in the beginning aswell, just set all knobs to NAV and the upper knob to hdg.

Hope this can help. ;D

Greetz
Bombayduck