You can call daily to add the additional dates one-day-at-a-time or wait until the appropriate day to complete the reservation. For a 10 night stay, you can reserve the first 7 nights 11 months from the arrival date and then reserve the other dates 3 days later.
Thanks! Called yesterday and made our first reservation at our home resort!!!! Now, I just have to decide at the 7 month mark if I want to do a split stay or not. So excited to try all of the resorts - don't know if I can wait to do only one a year......