Resigning in Person in Italy

Hi all,
Can someone advise me on the process to resign from my current work?
I know I can do it online but I do not have the PIN that INPS gives. My HR told me I will have to physically go to the Patronato and file the papers.
But I don't understand how this works, do I need an appointment? and what documents do I carry?
This information is not on their website.
So I am very confused and I need to begin this process by next week at its latest.

Have you tried calling them and asking?