Hi Bill,
In the attached screenshots you will find the 'overhead A/P switches', the top left two, the Pitch Trim switches, can only be switched on when your IRS has aligned.
If you feel uncertain with some of the systems, this youtube channel provides excellent explanations for the A300 for each phase of flight!
Youtube - A330 Driver - A300 tutorials and full flight videos: https://www.youtube.com/playlist?list=PLtFw-RsDhI867orKAa3qH-1YIu0fXNWF-
But you can of course always ask here!
Regards,
Kevin