Well, that is a bizarre thought. No, it takes about two minutes. But you can do it anytime in that four hour 45 minute window.
on embarkation day, open up the app and answer two or three short health question, and view the safety video.
your 11:30 appointment is your arrival time. You will actually board when the ship is cleared and ready for you
when you board, the rooms will be open and you can drop your carry-on there. They may not be 100% ready but you can leave your carry-on while you go to lunch, go to your muster station, explore the ship, etc..
So sometime in that window,, go to your muster station and check in there. That’s all there is to it.