How to enable the service
Open "Play Store"
Go to "My Account" under Menu
Under Payment method select "Omantel Payment"
Note: You'll need internet (not Wi-Fi) to set-up your account for the first time

How to buy an app after enabling the DCB
Choose your paid app
Select "Payment Method"
Select "Omantel billing"
Now you can easily purchase the app by clicking "Buy"