Once everything is configured, just start the POS as usual. You will see messages on the device when: * you start the POS, * you add or remove a product, * you select or deselect a customer, * you press the Payment button: the device will display the total amount, * you enter the amount of cash you receive: the device will display the amount of the change to give back, * you validate an order and go to the next customer, * you close the POS.