The assets displayed in the two panes are controlled with the left side bar tools. And, if the tablet user is the Current Presenter, they will see the Presenter Menu bar vs. the Attendee Menu bar. The images show the two different menu bars: Current Presenter and Attendee.
To maximize or minimize the left menu bar, tap the Menu icon.
Note: If the Current Presenter has not shared videos, presentations, documents, surveys, or unlocked the whiteboard, those options will not show in the menu bar.