I am planning to apply for the Z Visa tomorrow in New York, NY.

When on their website regarding authentication I was extremely confused in whether this applied to me. I called the embassy and the agent alerted me that I would have to "get it notarized, county clerk, and secretary of state". I have all my documents (Work Permit, Invitation Letter from China). so I am wondering what exactly am I getting notarized and authenticated from the county clerk and secretary of state? The application or the documents that have already been stamped from the Chinese officials.