You don't go directly to a 1040X. You do the amending process.
If your first return was efiled and Accepted or you mailed it, then you need to do an Amended tax return to correct or add new info. You need to wait for the original return to be fully processed and you get the first refund or paid the tax due. Then you can Amend. Be sure to save a copy of your original return before you start the amended return. The Amended return will overwrite the original return.
How to Amend the current year
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-federal-tax-return-curr...
If you don't see a button for Need to Amend a Filed Return? on your home screen then you can get to it here. Go to:
Federal Taxes -or- Personal (for H&B)
Other Tax Situations
last section, Other Tax Forms
Amend A Return - Click the Start or Update button
