Yes, it was the right word about leaving your belongings in your stateroom. You will be given a designated area to meet with all of the other people doing a B2B--it's usually around 10am after all the passengers have disembarked. Before you meet you will already have your new seapass card for the next cruise. You will all be taken off the ship and brought right back on. As you're boarding the ship you will have your picture taken with your seapass card just like you did the week before. The whole process should take around a half hour. You'll get plenty of instructions from the staff the day before. You'll be able to go right to your stateroom if you want. I'll be on the Allure when your on your first cruise. I wish I was doing a B2B like you. Having the same cabin makes it a lot easier when you do a B2B. We did a B2B2B in December and had 3 different cabins.
Have a wonderful cruise!