I am trying to figure out where I can enter distributions from my HSA and the expenditures on an amended return

The HSA is handled in 3 parts in the TT program :

First the contribution:

https://ttlc.intuit.com/replies/4557768

https://ttlc.intuit.com/replies/4785646

Next the limitations screen to confirm you are eligible to make the contributions:

Until you complete the HSA portion of the TurboTax interview to establish your eligibility for an HSA contribution, TurboTax will treat the amount entered on the W-2 form as an excess HSA contribution.

https://ttlc.intuit.com/replies/4788059

And lastly any distribution:

https://ttlc.intuit.com/replies/4787864

I hope that you were able to amend your 2019 return months ago, but for anyone else who finds this post, to add your distributions to an amended return, please do the following (once you have told TurboTax you are amending the return):

1. Do a Search (upper right) for hsa and click on the jump-to link (Mac users must find HSA in the Topic List). NOTE: just type in hsa and hit Enter - ignore any of the suggested search terms.
2. Click the box (if it is not checked already) that you have an HSA.
3. The next screen should be "Did you use your Health Savings Account (HSA) to pay for anything in 2020? Answer YES.
4. On the next screen, click on Add a 1099-SA if necessary.
5. On the next screen, enter the Payer information.
6. On the next screen, confirm your personal information.
7. On the next screen, add the numeric information from the 1099-SA.

When you have done this, you will want to send the IRS all the forms that changed along with the 1040X. Very likely, the only form that changed is the 8889. Even if the 1040 did not change, send it anyway; the IRS should figure this out.