how to file
Do not include your old 1040 nor your revised 1040 because the Form 1040X reflects any changes there and becomes your new tax return.
Include any new/corrected document only if it shows federal tax withheld, and include in order only those Sequence Numbered tax forms and schedules that changed or were added due to your amendment.
Attachment Sequence Number is on all the forms and Schedules that come after 1040.
Mail to the address shown for your location in the Instructions for Form 1040X.