I carried part of my 2016 refund over to 2017 (line 77, on 1040). I did not make any other estimated payments for 2017. Where do I enter this carry over?

You will need to enter it in the Estimated and Other Income Taxes section of the program. 

The easiest thing to do is log into your account and click Take Me to My Return (must click this first before the search or you won’t get the jump to link).  Click the search icon (top right corner magnifying glass) and search for "refund applied to this year" and click the "jump to" link that appears.  If you are using desktop then you can perform the same search within your program or search topics.

Or, you can also find the section by clicking on the following tabs:

• Federal Taxes
• Deductions and Credits
• You may have to click “Ill Choose what to work on” or "Show All" or "Check for More Credits" to get full list to appear
• Scroll down to Estimates and Other Taxes Paid
• Scroll down to Other Income taxes
• Answer Yes
• Scroll down to 2016 Refund Applied to 2017
• Enter your refund

If you don’t remember the refund amount, then you will need a copy of your 2015 return.  Look at your 2016 Form 1040 line 77 ("amount of line 75 [refund] you want applied to your 2017 estimated tax").  It its tucked below the routing/account number fields.