When I am using Firefox will it then always use Tor Browser? or do I have to specify it and use the Tor Browser in a qube, where I can find the Tor Browser?
qubes will never do it
by default, whonix-ws and it appvm have tor browser and should only use it here (depend on your skill, you can try it)
I don’t see how it depends on your skills. Simply run Tor Browser inside anon-whonix for a good enough anonymity.
As the previous users already mentioned: you better should use the main software which comes with Qubes as of software, you probably like from the past.
For your special question here: it’s simple! You HAVE to use Tor Browser in any “Whonix-like-qube” in this case anon-whonix and you CAN use Firefox as the main browser in any Fedora/Debian-like-qube, as it’s the only browser installed there in a main QubesOS installation.
Simpler: you only should use the Whonix-Qubes for accessing the tor-net and you should only use Fedora/Debian-Qubes for accessing the main-net.
to install it, sometime it could worse than using tor browser in whonix
Tor Browser is the default browser of
anon-whonix (a Whonix “workstation”) which uses
sys-whonix (a Tor gateway) to connect to the internet. As mentioned, just use these default VMs to browse with Tor Browser.
In this case, select
anon-whonix: Tor Browser (AnonDist) from the Application Menu and the necessary VMs will auto start, including
sys-whonix: Anon Connection which will walk you through connecting via Tor.