Hi Sagar,
The best way to learn knowledge on standard SAP is though SAP certification course material. You can also find multiple documents, blgs, Wiki pages realted to standard SAP in this community also . There are few books on released by SAP press you can also find helpful. Please refer to below threads:
Landing page for new users in SAP PP - ERP Manufacturing - Production Planning
Best Books for studying production planning | SCN
Regards,
Rohit