The Manage Presenters button in the Presenter Settings allows the host to select who will be presenting to the room. These settings also allow them to choose whether the stream will be cast directly to one room or all connected rooms at once!
When you Manage Presenters, you are able to choose where your Presentation is seen. You can toggle between streaming only to the room that you are currently in, or displaying your presentation to all connected rooms.
The Manage Presenters tab will show you who is currently presenting and give you the option to add presenters without stopping the presentation. After clicking on the Add Presenters button, just choose who you want to join the presentation and click 'Save Presentation'.