Can I start over? I asked TT assistant "How do I clear and start over?", but the answer didn't help. The is no menu available with an option Tax Tools, and no menu icon?

You must be signed onto your TurboTax account and then accessing the 2019 online tax return.  The Tax Tools link i s in the column on the left side of the screen.  If you have your display screen minimized so that the column is not visible then click on the 3 horizontal bars in the top left of the online program screen.

To access your current or prior year online tax returns sign onto the TurboTax website with the userID you used to create the account - https://myturbotax.intuit.com/

Click on Take me to my return

OR - 

When you sign onto your online account and land on the Tax Home web page, scroll down and click on Add a state. 

This will take you back to the 2019 online tax return.

If you have not paid for the online edition you are using, have not filed your tax return or registered the Free edition, then you can clear your return and start over with a lower priced edition. Click on Tax Tools on the left side of the program screen while working on the 2019 online tax return. Click on Clear & Start Over.