I'm trying to do quarterly taxes for self-employment, but it's taking me through 2018 individual taxes and I'm wondering how to get to the right place?

[VolvoGirl]

Yes.  To prepare estimates for next year you start with your current return, but be careful not to change anything.  For Online returns, 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 (Desktop H&B)
Other Tax Situations
Other Tax Forms
Form W-4 and Estimated Taxes - Click the Start or Update button

And don't forget your state.  Go to the end of the state section, probably under Other Tax Situations