Not sure what you mean by "claim " it---the stimulus check is not taxable. You will be asked about it--you will answer whether you received it in 2020 but you will NOT be taxed. (Edited to include the word NOT)
The stimulus check is an advance on a credit you can receive on your 2020 tax return. If something went wrong or you did not get the stimulus check this year, you can get it when you file your 2020 return in early 2021—if you are eligible.It will end up on line 30 of your 2020 Form 1040.
Just follow the interview ... everyone will see this screen in the Federal Review tab ...
Since the question about the stimulus doesn't happen until the END of the interview the program calculates the credit and includes it in the refund meter early in the interview .... but UNTIL you indicate how much you actually got in the ADVANCE payment it cannot know the correct amount is as you are not allowed to get it again. I think the timing of this question is not ideal however the Refund-O-Meter is not to be believed until you have completed the entire interview process. This is a question we will have to answer a lot I fear just like the "missing" EIC & CTC credits.
See information from the IRS:
This is like the story of Goldilocks in a way ... for some the amount they got in advance was too little, for some it was too much and for others it was just right. The EIP will be calculated on the 2020 information however if you got too much in advance you don't have to pay it back but if you didn't get enough then you will get more. Most people got the correct amount in advance to they will balance out exactly.
LOL ...Goldilocks ran down the stairs, opened the door, and ran away into the forest. She never returned to the home of the three bears. Much like the way I do on some of these questions.