Core php development - custom shopping cart with PayPal

Note: Full Payment will be made only on successful completion of the project. There would be no partial payment. First screen - Get the items with price from database. Include 3 more fields as 'Quantilty', 'Upload file in .doc and .txt format', 'Check box' in each row. Visitor shall choose any item by ticking on a corresponding check box in a row. Validate the choice for mandatory positive integer in 'Quantity' and a valid file in 'Upload file in .doc and .txt format'. Visitor shall click 'Order Now' Second screen- Appear as a shopping cart displaying all the items selected in the first screen with same detail. Each item with net price as a 'quantity * unit price'. Additional row with Total amount calculated as sum('quantity * unit price'). Visitor shall be able to delete any item from the shopping cart and should be able to check out with at least 1 item. In case visitor deletes all items from the shopping cart it should be allowed to 'Order again' by clicking on such button on the screen and control goes back to the first screen. On check out the order should be saved in the database with unique order id Third screen- Appear as a check out screen showing the items selected and total amount to be paid. Accept other details as a billing and shipping address. A PayPal button to accept a payment through credit card. This screen should be linked to the paypal test account created by you. Fourth screen- Notification screen showing the payment and order status to the customer. Additional order mail with necessary detail to the customer should go from our side. You should provide all the necessary detail to test your code.