1. Use the PMT function to calculate the periodic cash payments made on a loan.
2. Choose values for the different parameters: loan amount, interest rate, and number of periods.
3. To calculate the cumulative interest paid on a loan over a series of payments, use the CUMIPMT function and enter the corresponding parameters.
4. Enter the loan amount, the interest rate, the number of periods, the start period, and the end period in the function.
5. The CUMIPMT yields the cumulative interest payments over the specified range of payment periods.