question about W2 box 12a and IRA/Retirement

on my W2, under box 12 a, there is the letter S and a number amount. Also, the retirement box (13) is checked off.  I am doing deductions and credits and there's two areas where im a little confused 

 

Traditional and Roth IRA Contributions (Do i enter the amount of box 12 a here, as the amount listed is what i contributed to a simple IRA through payroll deductions) 
 
Retirement Savings Contribution Credit (it said I didn't qualify for this)
 
Please help!!!