PhilA , that's great, glad you made it.
In the meantime I found a manual in english language. If you want I can scan it sometime. It is however so that the control commands (letters for function selection) in the English variant is different to the German. Since you have the German operating system, this probably won't help you at first. How does it behave with the keyboard layout ? Some keys might be assigned incorrectly due to the different keyboard layouts.
Hopefully you will get the US version of the operating system someday.
I will take any data relating to the machine if it is available. I have the German version of the manual but my German is quite poor (aka I can't speak German at all...) so the rudiments of operation are quite difficult to understand. However, the way it works, even if the FUNC+key assignment is different, will be useful to understand.
The key assignment is as you'd expect, DIN. I'm not used to the QWERTZ layout and a few of the keys are accent modifiers as you expect to find.
I keep looking for people who possibly may have a copy- now that Fluxcopy is a thing, recreation of the discs is possible. I have hope that I'll find some.
Until then it is nice to be able to type at all, though the most common message the machine gives me is FEHLER. Go figure.