please help.. i would appreciate it if you could wirte down the steps and calculations by hand so i can understand

5. You have just graduated from and have been assisting your uncle in his owner-managed furniture business (Joshua Window Pty Ltd) while you look for your dream job. Your uncle is very worried about his lack of retirement planning. He is 45 years old and would like to retire at the age of 65 (i.e., 20 years from now). He has budgeted that he will need R15 000 per month, starting at the end of the first month after retirement date. He would like the planning to assume that he will live to 90 years of age (i.e., he will receive monthly pension amounts for 25 years after retirement). Assume that interest is 12% per annum compounded monthly. How much does your uncle need to invest per month, starting at the end of the current month and ending on retirement date (age 65) in order to realize his planned retirement pension