Installation not working

Hello everyone,

I am new to Zwift and already very very annoyed about the installation process. The pre-installed casette for the chain has a pre-installed nut in it which I could unscrew BUT when I want to install the nut again i can turn it for like half an hour and it‘s not going to hold. The nut is always falling of again as it doesnt have any grip. Any ideas?

Also I didnt got the adaption cards in the delivery and probably missing the thru axle components. What are your experience and can somebody help me out?