Hi Hari,
If your SAP system is new then you have to upload materials first. You can do this by creating LSMW or BDC. After creating material master, upload the intial stock to SAP system using tcode MIGO and mvt type 561.
Functional is creating BDC and Developer is creating BDC. In SDN you will get lot of links for how to create LSMW and BDC.
Regards
Vikrant