Kenny Zhao's tutorials are focused on Octatrack Mk2 but they should apply, for the most part, to the original model.
I'm feeling kind of lazy so just navigate via the video to his Youtube channel to see his other Octatrack tutorial videos.
Ezbot's Youtube playlist. He might have other videos that he forgot to add to it.
Random tip seen on Elektronauts:
Like on all Elektrons there’s a test mode.
Hold Function + power on.
