On your 2020 return, you will be asked about the stimulus money. Select Yes, then enter the amount your received, then the program will calculate if you are owed more money, or you don't qualify.
After the Other Tax Situations section of the 2020 TurboTax program you will be asked about the stimulus payment received or not received in 2020.
After you asked about the stimulus payment & you qualify, you will get the Recovery Rebate Credit (stimulus) on the 2020 federal tax return, Form 1040 Line 30.