Serious thread drift . . . .

I had never heard of the cruise line MSC until a few weeks ago. I have put down a deposit for a cruise on the MSC Magnifica for a four-month, round-the-world cruise starting early January, 2020. There are 46 stops, some for two days, and 26 countries involved. Starts/ends in Genoa. I'm pretty excited. How in the world do you pack for four months???