How do I file for multiple years? Do I upload all of my w2's in the income section?

No. You can't report prior year's W-2s on this year's return. 

To file a new prior-year return for tax year 2023, 2022, or 2021, you'll need to purchase and download that year's TurboTax software for PC or Mac, as TurboTax Online and the mobile app are only available for the current tax year.

For more details check here.