Step by step Explanation need.

Sub: Accounting Information System

Refer to the following narrative of EspressoCoffe to process the customer orders. Draw Level 1 DFD with appropriate explanations of the steps. Espresso Coffee processes a customer order in the following sequence. After receiving a customer order and verifying the customer's identity, the items' availability is verified. Upon availability of all items, the customer credit standing is verified. To verify the customer credit standing, an authorization request for the order total is sent to the credit card company. Upon receipt of the customer credit confirmation, sales order information is stored in the Sales Order and Sales Order Line tables. If the customer does not have good credit standing or any items in the customer's order are not available, then the customer order is rejected and customer is notified