*Need to see formula in Excel

If you currently have $10,000 in savings, and you save $750 each period, and you save quarterly (4) and there are 30 years until retirement, and you plan to be in retirement for 15 years, and your expected return on your savings before retirement (this is an EAR) is 8% and your expected return on savings during retirement (this is an APR) is 6%, and your expected annual return on savings before retirement (converted to an APR) is 7.77%

What is the amount you'll have in your account at retirement and what anount can you spend each period during your retirement?

And if you delay 5 years before starting to save for retirement, what is the interest rate you would need to earn to hit the target anount above? Convert from APR to EAR.

*need to see the excel formula