Open "Pay On Site" application and click on "Activation".
The first connection requires an internet connection.
Activation process is on going and can take a couple of minutes during first connection.
Keys are being downloaded automatically (if required).
When activation is completed, a pop-up appears with your store name and location. Confirm and you can start with your first payments.
If location does not match your store, contact customer support and don't use the terminal to process payment until told otherwise.