To start a conference, call yahoo_conference_invite with a list of initial members, the room name, and a welcome message.
To add more people to the conference after it has started, call yahoo_conference_addinvite.
If someone adds you to the conference, you can either accept by calling yahoo_conference_logon, or decline by calling yahoo_conference_decline
You can log off from the conference by calling yahoo_conference_logoff.
Send a message by calling yahoo_conference_message.
The parameter from is the identity that you want to use to send the message. If this is NULL, your default identity will be used.
NOTE: Except for yahoo_conference_addinvite, all conference functions take the list of members as an argument.
Have a look at yahoo2_callbacks.h for conference callbacks. Beware that there's a chance you could get a conf_userjoin even before you get an invitation to that conference.