On the screenshot of the speaker interface (stage) you will find numbering with the descriptions below to the individual panels, symbols and icons.
You can always expand and collapse the panels independently. Depending on the configuration of the session by the administrator, icons are present, not present, located on the left or on the right.
The agenda is located at the left navigation bar and can be expanded and collapsed independently as a panel (see above).
The agenda is set by the event organizer. It can consist of different breakout rooms. Mostly the agenda includes the time, length and title of the corresponding rooms. You will only see the rooms and time slots you are unlocked for. If you press "Change Room" in a time slot, you will enter the corresponding room.