Amend Tax fiing

If I amend my filing... (received an unexpected W2 for $78 after I filed and received refund) as I understand I go to my turbotax filing and click Amend.  Then I add omitted W2 info , do not change/review any other sections.  Then select File Tax to submit.  CORRECT?  Does Turbotax send complete info or issues a 1040X?  And does turbotax advise me of any moneys I owe and where to send such?  Thanks