Use the Text menu to set the font, point size, and style for your lyrics. If no lyrics are selected, these changes are global. If lyrics are selected, the changes affect only the selected lyrics, allowing you to mix fonts and styles.
At page 70, it says:
Select a font, size, and style (if desired) from the Text menu. This becomes the font selection for the current line. You can change the font information later for either the entire lyric line or individual syllables.
The statement at page 47 appears to be accurate; the statement at page 70 appears to be inaccurate. A font change made without selecting any part of the text appears to apply globally, not just to the current lyric line.
This raises a question not addressed by the manual (as far as I can see): how does one select an entire line of the lyrics?
When the manual is revised, perhaps it could also state the permitted range of font sizes. It would also be helpful if the manual stated that fractional font sizes are not permitted, and that the selected font size must be an integer, though an integer that does not appear in the drop-down size list will be accepted if it is within the acceptable range of font sizes -- whatever that range is. (For example: E502W did not permit me to set a font size of 12.5, but did permit me to set the font size at 13 points. Above 10 points, only even-numbered font sizes are shown in the drop-down list in the font dialogue.)