I stumbled on not knowing how to add 3 lines of lyrics into a section of a medley (in mm. 147-163). All other music has one lyrics line
After you use <Ctrl+L> to enter the "Staff Lyrics" set the number of lyric lines to 3.
For syllable locations where there are no lyrics to be placed you need to fill the lyric locations (each note/syllable location) with spaced underscores, one underscore per syllable. The underscore will not display but it takes up the space allocated to the syllable.
It is very important to place a space between each underscore as successive underscores that are not separated will be treated as a single syllable.
Remember that each verse has it's own tab.
There are other possible techniques but this will work and is easiest to imagine/explain.