Need help with advanced configurations

[EinKantHolz]

Is there a good tutorial how the location and advanced menus are working?
I have a nginx.conf file for a service like Bitwarden that requires a more complex configuration.
But whatever I'm doing, its not working.

I can paste the config here and if someone could help or explain me how one can use it with nginx proxy manager, that would be great.
Or otherwise how and where can I use this with the custom config files without "destroying" the working configuration.