Hi Sunil,
PBF is one of the integrated solutions provided by SAP with BW package.
Please download component installation guide (either 8.0 or 8.1), and follow the exact steps to configure PBF in BW system.
PBF datasources are not different than standard datasources of BW, before that get in touch with your basis team to setup RFC connection between ECC and BW system.
Thanks,
Saurabh