When I click on Schedule Meeting it allows me to add/change whatever details I wish (i.e., date, time, recurring meeting, video, etc.) and then at the bottom there is a button which says, Invite with Google Calendar. I can then, in Google Calendar, add as many guests as I would like and then save it to the calendar. My meeting then also shows up in RingCentral Meetings as well.
Are you seeing what I just described? (see my screenshot below)