To add a video for Philipp Chirstoph Kayser / Sonata No. 2 for piano, violin & 2 horns in E flat major, just enter the video‘s YouTube link:
example) https://www.youtube.com/watch?v=XXXXXXXXXXX
Search YouTube for Philipp Chirstoph Kayser / Sonata No. 2 for piano, violin & 2 horns in E flat major