I am Japanese, but for foreign tourists, I will describe the method from entering the store to leaving. When you first enter the store, there is a ticket machine. Insert Japanese yen into the ticket machine,choose what you want to eat, and press the button. If you want to add toppings as you like, you can also buy a meal ticket. Take a ticket and sit in an empty seat. The water is on the counter, so you pour it into your own glass. It will be served in 3 to 5 minutes, so please enjoy the taste to your heart's content. When you're done eating, say "gochisousadeshita" and say thank you to the staff before leaving.