Retirement tax questions

Enter the 1099-R then continue thru all the follow up screens in that section one by one ( don't stop or give up ) until you see this one where you can enter the contributions you made (then continue until you finish that section ... there are more screens after that and you must complete them all ) ... remember to leave box 2a BLANK ... do NOT enter a zero... and box 2b should be checked for not determined.