working mechanism of SBO DataTransfer Workbench

Dear All Gurus/Experts,

I have a problem relates to DTW working mechanism. I don't understand how system SBO will record imported data using form like AR Invoices, AR Credit memo, and so on. If it is master data like business partner, item, and chart of account, I clearly understand it because the system will automatically update or add it. So, is it as same as the form ? Will the system SBO update or add it automatically if I import the files relate to the forms to avoid one to one update or add ? I have tried using templates provided by SBO (in DTW) but still can't update or import. I appreciate your answer. TIA

Rgds,