How do the Gladers ask the Creators for something that they need?

I believe that the Glader prays sometimes putting a hand against his forehead.

They wrote a note and put it in the box.

Thomas was surprised. "You mean, you can make requests? Supplies you want?" Why would the people who'd sent them there help so much? "Of course we can. Just drop a note in the Box, and there she goes. Doesn't mean we always get what we want from the Creators. Sometimes we do, sometimes we don't."