I do not understand how to calculate annuity and put the formulas into Excel. Please help.

Marie, an employee at McCormick, has determined that she will need $5000 per month in retirement over a 30-year period. She has forecasted that her money will earn 7.2% compounded monthly. Marie will spend 25-years working toward this goal investing monthly at an annual rate of 7.2%. How much should Marie's monthly payments be during her working years in order to satisfy her retirement needs?