Waiting rooms are there as a way to refine access to your meeting. Once you create a meeting you can enable Waiting Room for it at
Meeting options then
Enable waiting room at https://cern.zoom.us.
That means that when attendees are joining the meeting, they will be in a waiting room and you need to grant them access, one by one or wait and grant access in a bunch.
You could also select who will need to pass by a waiting room either:
- all participants or
- just guests.
Finally at your profile,
In Meeting(advanced) ->
Waiting room you can customize description and logo for your waiting rooms.
Please see more details in Zoom article: Waiting Room.