A queue is a line of things, usually people. If you go to the store on a big sale day, there will probably be a long queue at the check-out.
Queue comes from the Latin cauda, for tail. Outside the United States it means a line of people or vehicles waiting their turn, so if your English friend talks about queuing up for the movies, that means getting in line for a ticket. We also use it in computing to mean an order of messages to be sent. In a big office, you send documents to the printer queue, and they're printed in the order they are sent.