please help using exacl

5. Each payment in a mortgage includes payment towards the principal and payment towards the interest (plus mortgage insurance, an escrow payment for the property tax, and, possibly, some other things). The interest in each payment is the current payoff times the periodic rate. The principal in each payment is the payment minus the interest. The next payoff is the last payoff minus the principal from the current payment. An amortization schedule is a table in which the rows represent the payments, the columns represent: the interest for this payment, the principal for this payment, and the current payoff. Prepare an ExCel (or similar software) file that will allow a user to enter the proceeds of a loan and the annual interest rate which is compounded monthly, and output the amortization schedule for a 15-, 20-, and 30- year mortgage (three separate ExCel sheets)