To enable payment, you have to log in with privilege level "Content Administrator" or higher. When logged in, access the Configure Payment section of the Admin menu.
First, configure the currency used to price your ad publishing services and the cost of a credit as well as the default set of fees expressed as a number of credits; a set of fees is made of several prices, each price is related to a service (currently, there are two services: advertisement insertion and advertisement renewal).
Then, configure at least one payment mode.
Lastly, enable at least one of the payment modes configured.
Optionally, you can add sets of fees if you want your ad publishing services to be priced differently for some advertisement categories.
To manage payments, you have to log in with privilege level "Moderator" or higher. When logged in, access the Manage Payments section of the Admin menu.
The Manage Payments section lists the payments, completed or not completed. The page displayed by clicking the "Details" link of one the payments, allows you to validate that payment*, if it is pending completion. To do so, change its status to "Completed". Validating a payment automatically impacts the advertisement related to that payment: a new advertisement that is pending for payment will be online; an advertisement for which a payment for renewal is made will have its expiration date modified.
Note *:
If you use Paypal as a payment mode, the status of the payments made by Paypal is automatically updated via the Paypal Instant Payment Notification (IPN) mechanism. But you can also validate payments made by Paypal manually, as described previously.