A few years ago there were relatively few videos available of the great liturgical chants, so that if you wanted to demonstrate the flow of a chant to a learning schola, it was sometimes hard to find what you needed.
Since then there has been a happy explosion of chant music available, in all sorts of voicings and with varying interpretations, such that listening itself is an enjoyable way of thinking and learning about the chant.
Here are a few very different versions of the Introit of the Day, Ad te levavi, as we begin our annual time of waiting for the Lord. To you have I lifted up my soul. My God, in you I trust, let me not be put to shame and let not my enemies laugh over me, because all those who wait for you shall not be put to shame.