A2Billing Configuration

I have installed following version successfully
Asterisk2Billing - Version 1.2.3 (BrainCoral) - Release : 13 August 2006
and my trunks and extensions are working fine in freePBX, now i want to set calling card application running on the same
What steps i have to take in order to run that, I have added some lines to extensions_conf file.

  1. Do i need to add one more trunk to A2Billing.
  2. Which number i dial from my extension to access Calling card IVR " Enter your card number"
  3. How do i set up that number to access Calling card application,

Please help