It's not that difficult but before you start, make sure you have either a paper or pdf copy of the original return saved in a safe spot.  Once you are sure that you have saved a copy of the original return, go into the 1040X and click the box to say that you are amending a 2019 return.  Write the reason for the amendment in the explanation area of the form.  Do the same for your state if your state has its own "X" form.  Then go in and correct the W-2.  Make sure the changes have flowed through properly on the 1040X and state and you are then ready for your next return.