Adding printer in TemplateVM not possible + printer authentication

I need some support while understanding QubesOS printer handling.

I will add a lpd network printer but the TemplateVM -Debian 10 do not show me the printer in system-config-printer. That is not a problem because i have entered the correct address in the host field. But if i want to add the printer the system is asking for authentication. Which password and name is necessary? I have tested many combinations…
In http://localhost:631/admin same problem, if i want to add printer system is asking for authentication…

I’m not quite clear on what your specific issue is, or from where the
request for authentication is coming from.
Is this a vanilla Debian-10 template?

You can certainly set up a networked printer in a template but because
the template has no network connection, you cant then connect to the
printer. That’s fine.
When you create a qube using that template you should find that the
printer set-up is there, and that you can complete connection to the
printer.
Have you tried that?

Did you read this in the docs?

In Step 2 it suggest giving the template network access - this is (imo)
a mistake and unnecessary.
Complete the set-up in the appVM, not a template. (If you want to be
able to print from many qubes, consider using a dedicated disposable
qube as a printer, and print from there.)

No, i use Qubes since march 2020 and i added some software in this qube like all others will do. The template needs network access to download software.

Yes, i have read the docs.

Why? to install software and add a network printer as described in the docs, the template needs network access.

I cant install the printer because the system is asking for authentication if i want to click “add printer” after i have choosen the correct printer in the list , username and password. I dont have the username and password, its not explained in the qubes docs…
As second idea i have used the cups interface but the system is asking for authentication if i want to click “add printer”…

Yes i want to print from many different qubes, is there any doc how to install a printer-diposable-vm?

You haven’t actually said where in the system the authentication request
is being generated. I’m assuming that it comes from the template.
In a vanilla template you can use sudo without authentication. But you
can also add a printer without sudo - I’ve just done it.
So you have have some change to the template that has removed this
capability.
The simplest thing for you to do is to get root in the template and run
system-config-printer

That should be enough to have the printer set in the template , and
necessary drivers installed.
I’m opposed to giving network access to templates unless its’ absolutely
necessary. In this case it isn’t. You can install the drivers etc in the
template and then complete the set-up in the printer qube.

There isn’t a specific document on creating a printer-diposable-vm,
because it’s just the same as creating any disposableVM Template.
Set up and configure the printer in the printer qube.
Then set the template_for_dispvms property for the printer qube.
That’s it - you can create a named disposableVM using that printer as the
template, or just spawn disposableVMs as you need them. I use a named
printerVM, but the choice is yours.