In addition to what everyone else has said, I make sure that newbies get a copy of our company's Member Benefit Binder, the one we give out to new clients. It explains all 4 of our corporations, our programs and services, who to contact for each corporation/program/service, etc. It also happens to have a list of the common acronymns we use for everything. :)
I also give them a tour of our website and the phone system. How to forward calls to voicemail, that kind of thing.
Seems kind of simple, but I remember how confusing this place was when I started!