This first recording, I start singing melody with you, and then you will hear the harmony part come in quietly while I keep singing melody with you.

This second recording, you will hear the melody at first to get you started (but soft), then you will hear the harmony part louder while the melody remains softly in the background.

This third recording is the hardest! You will hear the melody at first to get you going, and then on the second phrase the melody drops out and you need to keep singing the melody while you hear the harmony part only!