To prepare estimates for next year you start with your current return, but be careful not to change anything. If you can't get back into your return, Click on Add a State to let you back into your retun.
You can just type W4 in the search box at the top of your return , click on Find. Then Click on Jump To and it will take you to the estimated tax payments section. Say no to changing your W-4 and the next screen will start the estimated taxes section.
Or Go to….
Federal Taxes or Personal (Deskop H&B)
Other Tax Situations
Other Tax Forms
Form W-4 and Estimated Taxes - Click the Start or Update button