Hey Laura Frances!
Welcome to planDisney! You are correct in that unfortunately you cannot order a Disney band (or what Americans call MagicBands) until you arrive at Walt Disney World Resort.
Linking a Disney band to an existing ticket is very easy. The first step is to make sure you are logged into your
My Disney Experience account. Since you seem to have already connected to MagicMobile then it means that you should see your tickets and package connected to your account. Then, all you need to do is
LINK the numbers on the back of the center part of the band to your account, assign it to a person and you are done! Just remember that once you assign it to someone it is now their band forever. This can also be done on the
My Disney Experience Mobile App and directions are below.
If you purchased the fancier version of the Disney band with the haptics and lights then the best way to connect everything is the My Disney Experience Mobile App. Look for the three small stacked lines on the bottom right of your home page and click on them. You will then see an option called "Disney band and More." There is a chance if it doesn't update that it will say "MagicBand and More." Select your name/account and then click the type of band that you purchased that you want to be linked. There are a few options to accomplish that so pick whichever one you like and voila you are now all linked! Make sure that if your phone or new band needs charging that you do that before linking for the best success.
Don't worry though if you fail to charge your Disney band properly during your trip. It will have enough energy for a good while to allow you to enter your Walt Disney World Resort room, enter the Parks, access Lightning Lane entrances that you may have gotten using
Disney Genie+ service, and link
Disney PhotoPass images. It just may not light up or vibrate. Still a cute accessory though!
I hope this helps and that you have a fabulous time. Please let us know if you have any more questions.
Happy Planning!
-Nimmy