Retirement tax questions

1) On a return of contribution, any earnings would be reported in box 2a that would be the taxable amount reported on line 15b.

2) If you mean in the IRA contribution interview, you enter the amount that was withdrawn. If you withdrew the entire contribution then  enter that amount.  That would be the amount entered into box 1 on the 1099-R minus the box 2a earnings.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**