why do turbotax become so unusable. they got rid of the navigation menu on the left side of the screen. I can't do simple things like enter tax instalments.

The left side menu is available when you start entering some information on your tax return.

 

To enter, edit or delete estimated taxes paid (Federal, State, Local) -

Click on Federal Taxes (Personal using Home and Business)
Click on Deductions and Credits
Click on I'll choose what I work on (if shown)
Scroll down to Estimates and Other Taxes Paid
On Estimates, click on the start or update button

Or enter estimates paid in the Search box located in the upper right of the online program screen. Click on Jump to estimates paid