After entering your other tax information (income, dependents, deductions) there is a "Federal Review" step before going to your state return. In the federal review you will be asked how much stimulus you received, and if you qualify for more than you received, it will be included on your return. You can also go manually to the Federal Review tab at any time.
If you did not receive your first and/or second stimulus payment or if the amount received is not correct or if you did not receive the stimulus for a dependent child under age 17, you can claim it on your 2020 tax return as the Recovery Rebate Credit.
In TurboTax Online, to claim the Recovery Rebate credit please do the following: