You don't fill out Schedule 1 yourself. If you enter something that requires Schedule 1, TurboTax will fill out the form and include it in your tax return. There are many different types of entries that go on Schedule 1.
Why are you looking for Schedule 1? What are you trying to do?
If you just want to look at the Schedule 1 that TurboTax has prepared, in the desktop TurboTax software you can see it in forms mode. In TurboTax Online, previewing your 1040 will also let you see Schedule 1.
