General advice for sailing with Virgin Voyages,
Once you’ve booked, download the app and do the six check in steps, the final one is to choose the embarkation slot, the earlier times go first.
At 45 days to go you can reserve dinner restaurants in the app.
Then once onboard you can do fitness classes, activity and show reservations in the app. Some fitness classes fill quickly. There will also be more times available for dinner once onboard if you need to move something and you can book brunch in The Wake and Razzle Dazzle.
Hope that helps