Please elaborate. What do you mean the connection for the template disconnected? TemplateVMs should not be attached to a NetVM. Updates are done through a proxy.
You need to installing in whonix-ws-16, then shutdown the template and restart anon-whonix.
Because you are opening Firefox in debian-11 which is a TemplateVM and you are not supposed to do that. Instead, you should be creating a DispVM (Disposable VM) by launching one from the debian-11-dvm menu: Open the Q menu and find Disposable: debian-11-dvm. Launch Firefox from there.
Run sudo apt update before the install command.
It seems from your post that you might not know exactly what you’re doing, so may I suggest that you read the Getting started guide: Getting started | Qubes OS
Running software/connecting a template to net may be considered a security risk, so keep that in mind while you’re managing your VMs.
No problem, you should select it as answer so that question can be considered resolved.
To run a browser behind sys-whonix, it’s recommended that you use a disposable vm based on whonix-ws-16. To do that, open the Q App Menu and find Disposable: whonix-ws-16-dvm and launch Tor Browser from there.
If you want to install putty in the whonix template: