You book a reservation for a night earlier than your travel dates. For example, you book today 11/30/2026 to 12/8/2026.
Then a few days in, for example on the 6th, you modify your reservation to be 12/6 to 12/13.
Then again, on the 11th, you change the reservation to be: 12/11 to 12/18
And so on, until you reach the dates you want.
Doing it this way, once you have booked the first reservation, you're sure you'll get the nights you want, if you continue walking*. For hard to get rooms, this gives you multiple mornings to be able to book your first reservation, if it's unable on the first day, you can try again the following day. If you wait to book on January 29, then you have only one shot to book the room, if it's not available that day you need to hope in a waitlist (or stalking).
You could in theory wait for the last day of your reservation to move it, but I'd say give yourself some margin, so if something happens and you forget or are unable to login, you still have the following day to change it.
In my example I've booked one week, if you don't have enough points, you can still walk with 2 days, but you need to login and modify it daily.
For most rooms types most of the year, it's not really needed.
* it's very rare, but if Disney blocks a few rooms for certain dates, for example for a refurb or maintenance, it's possible you won't be able to continue the walk. Sometimes, a glitch happens too and some rooms are not available at 11 months + a few days, but become available later, this can disrupt a walk too. Also, you cannot walk online across different UY, you need to call for that.
