Like many churches you probably include Silent Night at your Christmas Eve Service. You also probably light candles during the singing of the carol, and this is what the Silent Night Underscore is for! Play it before, during or after Silent Night:
Before: read an appropriate Scripture.
During: sing a few verses of Silent Night, play the Underscore while you explain/distribute the candles, sing the final verse.
After: wrap up your Chrismtas Eve service and dismiss.