I love a good Christmas Carol, and this a cappella version is great. Recorded using a technique where you are singing with yourself and doing all your own harmonies it is very clever. But ignore how clever the video is, and just enjoy the hymn. Why not simply listen to this and get your group to think about why Christmas is so important. Or if you are being clever you could listen to the song and then talk about how the reality for Mary and Joseph might have been somewhat different to the picture painted in the carol!