If you go to the HSA section found under Medical Deductions, you should find a screen
"Did your employer tell you about any other contributions,"
Answer YES.
then on the following page put this amount in the box titled:
"Employer and payroll contributions not reported Box 12 of your W-2."
This is helpful, but I've not been able to get to this page. I may have seen it before but skipped past it. How do I get to it again?
If you go to the HSA section found under Medical Deductions, you should find a screen
"Did your employer tell you about any other contributions,"
Answer YES.
then on the following page put this amount in the box titled:
"Employer and payroll contributions not reported Box 12 of your W-2."
Was this $750 contributed through your employer (like, through payroll deduction), or did you contribute this $750 directly to the HSA (like by writing them a check)?
If the former, then rebab's instructions are correct. To get to that page, restart the HSA interview (Federal->Deductions & Credits->Medical->HSA MSA Contributions), and proceed through the interview. If you go through the entire interview and don't see it, then restart the interview, and when you are asked, "Did you (or anyone) makes contributions to your HSA?", then answer "yes".
On the second screen after, you will see the screen that rebab refers to.
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If the $750 was contributed directly to the HSA by you (and not through your employer), then on the first screen after "Did you (or anyone) makes contributions to your HSA?", you will see "Let's enter your HSA contributions". In this case, enter your $750 on the second line (any contributions personally made by you).