If you are working on the 2019 tax return using the online editions, there are several links on the left side of the screen. If you do not see those links then your screen has been minimized so they will not be visible. Either expand your screen or click on the three horizontal bars at the top left of the program screen.
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.