To add a video for Adam Gumpelzhaimer / Ecce quam bonum et quam jucundum (Florilegii Musici Portensis, No. 23), just enter the video‘s YouTube link:
example) https://www.youtube.com/watch?v=XXXXXXXXXXX
Search YouTube for Adam Gumpelzhaimer / Ecce quam bonum et quam jucundum (Florilegii Musici Portensis, No. 23)