We just did a B2B on the Ascent in FL. We had to meet at 830am in a meeting room. Time and place to meet varies by ship and port. Process takes 15 minutes unless there is an inspection that day. Then it could vary from up to an hour. There could be 10 to150 people doing this process. Just go with the flow and read your instructions and listen. They may give away prizes depending on how many. It all depends on the ship. They give away wine, spa credit, X stuff, and speciality rest meals. This was last cruise on Ascent where about 60 were on B2B. In other words it varies all the time.