American marrying a Bulgarian in bulgaria/what exact docs. do I need and/ Have to get them all apostille?

Basically--I've read that you have to have birth cert. apostile. and also have a "Single Status Affidavit" apostile...then on the gov. site it states that the only document you need will be provided when you swear before a U.S. consular officer..at there office. Will I still need to have a copy of my birth certificate apostile....or any other document apostile?? Or will my passport be all that I will need--as this has all information on it. Please help me...Thank you all very much.