After you create a data Item in the system, then the Proposal will have the code to specify the Item code for this Proposal in the customer information (Customer Master) ordered regularly.
After creating an information system in Item Proposal Item Proposal to code this code to identify the customer (Customer Master) ordering them regularly.
After creating the information system Item Proposal to Item Proposal code using this code to enter in the customer information (Customer Master) order them. On a regular basis.