The disc menu text page is one of the customization pages that you access using the toolbar buttons on the "Ready to burn disc" page (what we call the "hub page" internally).
The right side of this page has two previews. The top preview is the main DVD menu that will show up when you start playing the DVD. It shows the state of the menu after any intro animation has played. On it you will see the disc title, play button, scenes button, and notes button, and the text of each of these is set using the editboxes on the left side of the screen. The font, text color, and boldness and italicality of all the text is set using the font controls at the top of the screen.
The bottom of the page shows the notes pages preview. This is an optional page that you can use to add some notes about the DVD. If there is text in the Notes editbox, we'll create the notes page, and if there is no text, the page does not exist (and there is no "notes" pick on the main menu).
Changing any of the settings on the left side will start an update to the appropriate preview windows on the right side. This may take a few seconds, since we're using the same rendering process on these previews as we use to create the menus that we put on the DVD.
Red vs blue can be found here.