Amendment form 1040NR-EZ

hello, I have to amend a form 1040NR-EZ because I forgot to claim incomes after receiving a new form 1042-S.

 

IRS website states that I am suppose to fill out a form 1040-X and just attach the updated 1040-NR-EZ writing "Amended" on the top part. Is that correct? Is this apply to any type of amendments? It is kind of confusing because I don't know if I have to fill out all those complicate blanks from columns A, B or C or only fill the part where I state the reason of my amendment. I hope you guys can help me.