Now that you have installed Order for Customers you can start using it with your administrator account. But you can also create users (or grant already-existing users) with restricted rights, as to order for customers.

• Go to “Users” tab
• If the desired user already has an account click on All users and click on his name in the user list. Else click on “Add new” button.
• Find the “Role” field and choose “Operator” in the select box.
• Fill the other fields with his personal info.
• Click on “Create” / “Update” user button

You just granted this user additional access rights. He can now order for customers at checkout. If you add him as calendars manager, he will also be able to manage bookings made on those specific calendars.