I am in the midst of filling info out up to W2. I did not answer yes to retirement income. How do I go back and add that?

Don't worry about the beginning questions.  You can add your 1099R after the W2s.  

You can just type 1099R into the search box at the top of your return, then find and it will give you a Jump To link to go right to it.

OR Enter a 1099R under
 Federal on left
Wages & Income at top
 Then scroll way down to Retirement Plans and Social Security,
Then IRA, 401(k), Pension Plans (1099R) - click Start or Update

If you get the screen of partners you can import from click the bottom circle for I'll type it in myself - Continue
The next screen should be What Type of 1099R is this?  With 4 choices.  Pick the right kind you have.
And on the same screen you pick which person it is for if you are married.