You have to be out of your room I think at 7am. Like everyone said you eat breakfast in the dining room you were last at. Topsiders wasn't open on my last cruise. Breakfast is fast and the magic has stopped. The waiter takes your order, drops it at your table, and you never see him again. It is a very small breakfast so take the danish they offer. Nothing else will be open.
Unless you are in a suite, you are out of your cabin when you leave for breakfast. Your breakfast time it determined by your dinner time. If you have early (main) seating, you will have early breakfast; late seating = late breakfast. If you don't like your assigned breakfast time, you can eat on deck 9; they stop serving at 8:30.
You are asked to be out of your room by 8, but we had 8:15 breakfast; I stayed in the room until about 8:10. You are supposed to take all your carry ons with you and not return to your stateroom after breakfast. Yes, I've read here about people making arrangements with their room host to leave their stuff--the problem with that is that the room hosts will make their lives easier by propping open all the doors and working several rooms at the same time. They can't do this if you have personal stuff in your room.
You put your luggage outside your room by 11 the night before. If you are on a participating airline with onboard check in , you won't see it again till you arrive at your home airport. For all other transportation arrangements, you will collect it in the terminal to go thru Customs.
I can't explain PP's remark about Topsiders not being open--it has been open on each of our 20 cruises. If you haven't cruised recently, we were pleasantly surprised by the last day breakfast improvements in the dining rooms. Yes, the selections are still limited, but MUCH expanded from what they were a year ago. The servers are busy, and won't be fussing as much over drink refills, etc, but we were able to get what we ordered, and they brought DD 2 glasses of juice to start so they wouldn't need to do a refill.