Here is a 20-second video of a restaurant menu application that you can start and restart manually.     

     You’re going to see the user choose “Salads” from the Category list at the upper left. This event will populate the upper-right list box with menu items in the “Salad” category, and, when the user selects an item, the selected item’s description and unit price will appear below that.

     Then the user will enter a quantity and click the “Accept” button, which will cause the “Item Total” to be calculated. A new “Order Item” record is also created; it has “Item Total” and “Quantity” fields plus the fields of the chosen “Item” record.

     Then, clicking the “Order” button adds this new “Order Item” record to the shopping cart list box just below, and the “Order Total” display is recalculated.