First job lot of questions?

im 15 and have called everywhere and the only place who will hire is dairy queen ..so i want to apply and am wondering what to expect.. when i turn in my application are they gonna want an interview? what questions will there be? and how should i dress and stuff to let them know i am mature? and what job do you think theyll give me to do like wash tables, make food, or cashier? thanks for any help :)