Hi, in short, is the "backoffice" of your app. The "place" where you receive all the orders, bookings, chats and so on. You can login to the workstation with any device and use it to process the orders. You can check the detailed documentation "Understanding Workstations" https://www.zappter.com/docs/en-us/zappter-core-functions.html?i=11
Depending on your business type. Let's take as an example a Food Truck business that created the app to let customers order faster and avoid long queue. With two different workstations; one for food and the other for drinks, they could be able to complete the drink order and give you the cola while you're waiting for your hot-dog. In conclusion, using just one or more depends on how you run your business.