When you arrive come through the archway, there will be somebody from Biltmore Security who will stop you at that archway. He will put a green wristband on you which will allow you onto the estate. The main drive past the Biltmore House will be closed and signs will direct you to Rally Central. Someone from Security will assist you in finding a spot to camp.
You must get back to Registration at the Welcome Center to register the next day and get your proper wristband for the rally.