Start with a small talk revolving around: the restaurant and fastfood they love, the restaurants/fastfood they have in their town or neighborhood, or the food they want to eat everyday.
Present the fastfood they are going to have for the day. I just named it after the name of the school. You may have other unique fastfood name or even change the price from the menu. You can make it cheaper or extremely expensive. It usually gets students' attention.
Present the menu, read them with the class, and followed by script practice. Demonstrate with JTE (as the customer).
After the demo, practice for one last time before pair group. Let students be the staff and the JTE as the customer,repeating the same order he made.
Give students the menu copy (1 each pair) and the receipt (2 copies each students, depends on how many times would you like them to do the script)