Rainer,
I can try to help - it will come with some questions to help understand your statement 'can not get going.'
Which version of NINA are you using? I'd recommend updating to the latest stable version.
Are you able to see QSI ASCOM driver in the NINA camera selection list?
In the past, I have had trouble with getting ASCOM drivers to work with Windows 11. I found that the solution was to downgrade the QSI drivers to version 7.4.1824. I hadn't seen any substantive differences with the older drivers, they work just fine.
I have not tried the latest 2023.06.16 version of the QSI drivers, so cannot comment on those.
Roman.
