How to Populate the Net Profit field of a Sales Order to Deals Net Profit field by subform's aggregate data

How to Populate the Net Profit field of a Sales Order to Deals Net Profit field by subform's aggregate data

I'm trying to populate the Net Profit from Sales Order Module going to Deals Module. I'm using an aggregated Field in the Sales order module and trying to map the Net Profit to the Profit under Deals Modue. Please help me writing the code.