To add a video for Clifford Harker / Pastorale: The Rosy Sequence (from 3 Preludes based on plainsong themes), just enter the video‘s YouTube link:
example) https://www.youtube.com/watch?v=XXXXXXXXXXX
Search YouTube for Clifford Harker / Pastorale: The Rosy Sequence (from 3 Preludes based on plainsong themes)