We caught a cab here from the airport because we weren't really sure about public transportation…read moreand it seemed a lot more complicated. Our cab driver knew exactly where to go when we showed him the address and port, so I would suggest just taking a taxi if you are able.
We arrived a bit earlier than planned, and we were glad, as there wasn't a large crowd or line at the front entrance. Had we not gotten information from our cruise line, MSC, it may have been a bit confusing. There was one attendant who couldn't really answer any of our questions and only pointed us to bag drop-off. Some of the other passengers spoke English and were able to help us out. Once we checked in our luggage, we headed inside. It's a very large and open area, cold and without much of an atmosphere or view, other than staring straight at the side of the cruise ship. There are washrooms and a small café with minimal snacks for purchase.
We weren't really sure what to do from here, so we asked one of the attendants at the counter, who told us they would call our number when it was our turn to board. Other than that, it's really just a waiting game. I would suggest bringing your own water, snacks, a sweater, and something to keep yourself occupied, as well as sitting close to where you get in line. The seats can get pretty uncomfortable after awhile, and you have to pay attention to when they call for boarding, since they weren't using any kind of PA system while we were there.