Please explaine it step by step

Caveman Manufacturing took out a loan for specialized manufacturing equipment requiring six large loan payments in the future. Caveman will make the first payment of $25086 at the end of year 20 and each subsequent payment will increase by $8600 over the previous year. Caveman would like to save for these large payments by making 19 equal deposits at the end of each year. What amount must Caveman deposit each year in order to make the future loan payments? Assume an interest rate of 2.5% compounded annually