Draw a level-0 Data Flow Diagram using VISIO that shows the appropriate details for the point of sales system described below. Remember this is a level 0 data flow diagram not a level 0 context diagram!

Self-checkout system at Big Joe's Supermarket uses a scanner to read universal product codes (UPC). When a customer scans a product, the system reads the code (i.e., barcode) of the product and retrieves product information based on data stored in a product file. The system displays the product summary to the customer. When the customer provides payment information, the system verifies the payment information by connecting to an external credit/banking verification system. Purchases made are stored in a file to be used in printing the receipt. After the purchase has been made a receipt is produced and given to the customer.

This question has been answered wrong multiple times, do not attempt to answer if you don't know what to do.