I need to file an amended state return. The instructions say do not file your original return, yet they also instruct you to attach the original return. What do I do?

I am using a DVD/CD version of TurboTax for 2021 and preparing my own taxes. I filed and have received my refund, yet I need to amend the return. The return for the Federal was filed electronically, but the state return must be mailed. Instructions say "Do Not Mail", and later say to attach the Schedule X to the original return. Which do I do?