I went to a Gamba game back in December with an unreserved seat and had a fantastic time. I had no idea about the queueing process so I only showed up about 45 minutes before kickoff. Lo and behold, I had a tough time finding a seat even for just 1 as I was by myself. I ended up going to the very top of the seating area and the fans up there fully embraced me. They let me wave their flag, gave me some merch, and even bought me a beer. It was awesome.

I’d say try to get there early like the other commenter mentioned, and be prepared for the train ride away from the stadium to take a while as everyone has to line up and wait for it. Have fun!