Hi Srinivas,
I suggest to first have a look at the SAP Help for Business Content DataSource. You might find information on the source tables here.
As a next step you can have a look in the coding of the Function Module or debug it. You have to look to statements like TABLES and SELECT.
As a last step (and maybe time-consuming) execute an SQL Trace using t/code ST05 during executing t/code RSA3 in the Source System.
Best regards,
Sander