How to update Listbox Items and Print Asterisks?

Question

Need a Visual Basic program. A list box containing five stores (all five stores set to a revenue of 0). The user should be able to update the revenue (and maintain therevenue) by typing the revenue in a textbox (and then clicking a button). The program also needs to print out asterisks (*), each asterisk represents 100(printed out as a chart). If there is 0-99 revenue, no asterisk is displayed. The selected index should also be displayed by clicking a store. Can you please help with the coding?