What are you trying to do? Do you mean you are trying to fix it in order to e-file it? Or are you trying to make a change to a return that you already filed?
What link are you referring to?
If you e-filed your tax return and it was rejected, just sign onto your online account -
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 2020 online tax return where you can make any changes to correct the error and then e-file the 2020 tax return again.