The number of members of the Board, the manner of their selection (including the filling of vacancies), and their terms of office shall be as provided in the constitution and bylaws of the Foundation. However, the Board shall have at least 11 members, two of whom shall be the Secretary and the Assistant Secretary of the Interior for Indian Affairs, who shall serve as ex officio nonvoting members, and the initial voting members of the Board shall be appointed by the Secretary not later than 6 months after the date that the Foundation is established and shall have staggered terms (as determined by the Secretary).