Hi Shravan,
In order to get the customer open items, you need to run the below two transactions.
1) FDM_COLL_SEND01 ( Program :FDM_COLL_SEND_ITEMS, for Periodic data transfer)
2) UDM_GENWL (Program : UDM_GEN_WORKLIST, to generate the worklist)
Thank you,
Krishna