These four buttons select which of the Audio Notetaker panes are visible on your screen. (you have to have one visible at all times)
From left to right they are:
Image Pane – Your slides and images will appear here (one per section)
Reference Pane - This is free text section. Useful for reference material about your presentation
Text Pane – This is free text section. Useful for taking your notes on your presentation
Audio Pane – Your recording will appear here in blue chunks.