I'm afraid I don't remember. I went through a lot of unfamiliar gui, trying different things, and I can't seem to find that screen again. I managed yesterday to configure it without getting a password prompt (seemed completely random), but even then, it didn't print, nothing happened. I tried for hours desperately trying to get it to print something, but to no avail.
I woke up this morning, and all the paper available to the printer had been used while I was sleeping, while the computer was OFF. The pages told the story of everything I had tried to print the previous day. It had taken about 9 hours to respond, but it printed all of it alright.
After that, my printer started behaving again. Now it prints things instantly. I'll never know what happened, but at least it works.
Thanks for trying to help though.