To add a video for Jacobus de Kerle / Agnus Dei on the hexacord ut-re-mi-fa-sol-la, for 5 voices, just enter the video‘s YouTube link:
example) https://www.youtube.com/watch?v=XXXXXXXXXXX
Search YouTube for Jacobus de Kerle / Agnus Dei on the hexacord ut-re-mi-fa-sol-la, for 5 voices