Create Customer Group:
In your restaurant manager (cloud.gastrofix.com) navigate to the tab "Customer Group".
("Operators" --> "Customers" --> "Customer Group")
To be able to create a customer, you first need a customer group. Now click on the "Add New" button to create a customer group.
Now define the desired "Name" for the group. The "Discount" is not a mandatory field and can be left blank.