mfberlin website is no more - I found a users guide here:

https://github.com/5-lagu/mfb-seq-03-manual/tree/main
-- jpn9900

Hey! I made that, based on an old PDF I found on an archived version of mfb.de the Wayback Machine. Let me know if you found it useful and if something is not right. I sold my SEQ-03 but I'm maybe buying one again... It's a bit awkward to use, but super powerful and flexible once you get the hang of what all the buttons and shift-functions do.