On the black menu bar at the top of the screen, select VIEW and then select FORMS. You can then view the forms at the point where you are and then once you want to go back, Select VIEW then STEP-BY-STEP.
@Tinkertoy Depends...the question came from a user ( @mattmillsnj ) who indicated they were using the "Online" version for TurboTax. Your answer is good for "Desktop" but not "Online" software users since the navigation menus are entirely different.
So if the indication of software type was accurate....the "Tools" menu on the left-hand side is only available once you get somewhere inside your 2019 tax return. So:
1) if you have not actual filed your 2019 taxes yet, so after you first log into your account, you need to "Continue" or more likely "Pick up where you left off" into your 2019 file first on the main screen....then the Tools selection will show up. (Actually it's <Tax Tools....then <<Tools )
or
2) IF you have filed your 2019 taxes already using that TTX account, there is a selection to just download your entire 2019 tax return from the main screen, as a PDF file. Then you open that PDF file to see your form 1040.
Also some other subtle steps if the PDF in #2 does not contain your 1040.