You have to bring all the documents that you submitted to nvc the original documents, also all the evidence of the relationship photos etc and you have to answer what they ask don't explain what they don't ask you to answer. But you can just say a little bit more for some questions like: when did you meet? you tell the date and you say "in a party" or something else, but not more info unless they ask you for more details

@ mm am in the same situation