Please do this out on paper and not excel

John purchased a treasury bond with exactly six years until maturity, which pays coupon annually. The bond has a par value of $1,000, a 8% annual coupon rate, and a current yield to maturity (YTM) of 7%. After exactly three years, John sold the bond to another investor, with the yield to maturity of 6%. He was always able to re-invest all his coupon income at a return of 4%. All rates are annual. What is his geometric ANNUALIZED average holding period return over the 3-year period? You must provide detailed calculation to receive credits