Most visitors from cruise ships in Zeebrugge take the coastal tram to Blankenberge like T. already notes and from there the train to Brugge station.
The Zweedse Kaai close to the large sealock, is usually the place where the ship will dock. You have just to walk to the main road leading to Zeebrugge Dorp. The walk from the ship to tram stop “Zeebrugge Kerk” is about 10 to 15 min., located opposite the church you actually can’t miss. Not sure if the winter schedule is already changed into summer schedule in April, but expect you can catch a tram every twenty minutes. There is a timetable at the platform, use the one for direction “De Panne”. Tickets for the tram costs €3 per person for a single journey, there is as far as I know no ticket machine there, but the driver sells them anyway. Be sure he validates the ticket, if not ask him or use one of the yellow machines you can find at the entrances of the tram.
The tram stops at “Blankenberge Station” opposite the train station in Blankenberge, you have to buy another ticket for the train to Brugge. The coastal tram with direction “Knokke” will bring you back to Zeebrugge at the end of the day.