Can I save/reserve a Qantas OneWorld Classic Flight Rewards (RTW) booking?

Hi to the brains trust.
Just a couple of questions about booking a RTW reward for next year.
I can see on the Qantas website that I can book the first two legs of my trip with BC tickets available.
As the dates for the rest of the trip are not yet available, should I go ahead and book them? If so, from what I have read so far, I would have to ring Qantas to add the remaining legs as they become available. Would this incur the 5000 point booking fee each time I do it or can you save the itinerary online and add to it at a later date?

Hi,

You’ll have to book what you can on the website and ring up to add/change flights to the same itinerary each time.

I.e. you can’t save/reserve the award seats.