Mary Lee usually likes to give some of the verses to small groups of voices so be prepared (with a pencil preferably) to note which parts of the piece she wants you to sing or not sing.
The high soprano solo near the end of the piece is included in the soprano track. Don't let that throw you, sopranos.
To play the track, just click on the line you want to listen to. You can fast forward and rewind through the track by dragging the little moving line. To pause playback, click on the pause sign on the album cover.