Click on Options in the tool bar below the main menu and, on the left, select Project Options - Display data. This dialog is used for defining the parameters for Notes window 1. Altogether there are four video notes windows, with the other windows being selectable upon clicking the plus sign in front of Notes window 1.
Place a checkmark next to Display during playback / Presentation to enable the notes window.
Under Font you can select the corresponding font used for the notes window.
Under Font size you enter the corresponding font height in pixels.
Select colors in the selection dialogs for fonts and background by clicking on the fields next to them. Details on color selection
See also