I'm creating, for class, setting up a small cafeteria for the workers in the building. How do I start?

Not sure at what point you want to start
Simply setting up would include
You would have to get an idea how you wanted to set up most efficiently
Then consider your supplies and equipment

Like dishwasher, stoves, ovens, grills, refrigerators, coolers, pop machines, dishes, pots, pans,.
You would also have to get an idea of menu, how many you plan to serve, what to order
Where to order from and how much to order.
Set up a weekly/bi-weekly schedule for deliveries