There is no "new" $600 federal stimulus. You may have misunderstood something.
There have been three stimulus checks --- also called EIP payments. The first one was for $1200 and was sent out in 2020; the second one was for $600 and was sent in either late 2020 or early 2021; the 3rd one was in 2021 and was for $1400.
If you did not receive the 1st and/or 2nd EIP payment you can get it by filing a 2020 tax return and using the recovery rebate credit.
If you did not receive the 3rd EIP payment you can get it as a recovery rebate credit on your 2021 tax return.
@Harryou If you did not get the 3rd stimulus of $1400, use the recovery rebate credit on your 2021 tax return. Go to the Federal Review section to that credit and answer the questions. If you are eligible for the credit it will show up on line 30 of your Form 1040.
PREVIEW 1040
https://ttlc.intuit.com/questions/1901539-how-do-i-preview-my-turbotax-online-return-before-filing
Click on Tax Tools on the left side of the screen. Click on Tools. Click on View Tax Summary. Click on Preview my 1040 on the left side of the screen.