please help with drawing a level-0 physical DFD for the problem

Develop a level-o physical DFD for the following business process: TD, a vendor, sends an invoice to VCU for data warehousing support services. The invoice is sent directly to Anderson Longstreet, the accounts payable clerk, who records the invoice in the accounts payable file. Once the invoice is recorded, it is forwarded to Mary Johnson, the cash disbursements clerk, for processing. Mary prepares a check to pay the invoice and sends the check and invoice to Jackson Sternburg, the company treasurer. Jackson approves and signs the check and cancels the invoice. Jackson then mails the check to TTD and returns the canceled invoice to Mary for recording in the cash disbursements file. Develop a level-o physical DFD for the following business process: TD, a vendor, sends an invoice to VCU for data warehousing support services. The invoice is sent directly to Anderson Longstreet, the accounts payable clerk, who records the invoice in the accounts payable file. Once the invoice is recorded, it is forwarded to Mary Johnson, the cash disbursements clerk, for processing. Mary prepares a check to pay the invoice and sends the check and invoice to Jackson Sternburg, the company treasurer. Jackson approves and signs the check and cancels the invoice. Jackson then mails the check to TTD and returns the canceled invoice to Mary for recording in the cash disbursements file