I recommend you go to the Newbies Section
... above the metal mouth forum and spend some time reading the articles our webmaster has put in there. There are pics of the most common things associated with ortho treatment, about how teeth move, soft foods etc.
Many ortho's still use bands on the back molars. Some like to put these on ahead of the brackets. I'm not totally sure why, but I suspect it's a comfort issue and maybe helps the gums to settle before the brackets go on.
The band works to hold the archwire and a few other appliances if they're needed. It will also have a hook to anchor elastics and/or powerchains, if they're needed.
Encourage your daughter to rinse once daily with warm salt water ... it's great for the health of the mouth and makes it feel loads better if a little sore.
Good luck to your daughter!