a function to process the information.
Your form should have a place to enter the name of the product, the price of the product and how many you want (quantity).
The price and quantity should be multiplied to give the amount due and that should show on the form.
You should have a place to enter the number of payments you want to make.
You should then do a calculation with the amount due and the number of payments to determine the amount for each payment.
The amount of each payment should show on the form.
You should use buttons to handle the calculations.