You need to file a 2020 return to claim the missing Stimulus payments. It's too late to be based on 2019 or 2018 returns. If you don't need to file a 2020 return then enter $1 of fake interest to efile.
Then When you go through the federal review tab it will ask how much you got if any. Or to enter your stimulus payment in TurboTax, type "stimulus" (without the quotes) in the Search box, then click the link that says "Jump to stimulus." Say no to the amounts it shows you. Then 2 boxes will open up for each round. If you didn't get one enter a 0 in the box.
After you have entered your tax information and are ready for the Federal Review, it will be the first question.
If you are trying to trigger it, you can go to Other Situations, answer any questions and click Done. The next automatic selection is Federal Review and it will ask about payments received.
The Recovery rebate credit is on 1040 line 30. It either adds to your refund or reduces a tax due.
Thank You or your input
The main problem I have now is trying to get my refund from 2019. They received my return on 10/04 and still haven't processed it. Anyone know a magic number to talk to a real person at he IRS?