"Here are two bottles of beer for you!"
Translation:Jen du boteloj da biero por vi!
They accept "Jen estas du boteloj da bieron" as well as "Jen du boteloj da bieron." I think Jen is a rare idiomatic Esperanto preposition/interjection type of word that can mean "Here are/is". I think it is meant for when a person is literally holding the thing being spoken of, perhaps?
A beer bottle is the actual glass object while a bottle of beer is the object and drink. Same goes with glass of wine vs. wine glass, bowl of soup vs soup bowl, and pot of gold vs gold pot. So just the two words together is the second noun being described by the first noun, whereas when connected with of they are the container as the first noun and the thing inside the container for the second noun.