The government and supervision of such libraries shall be vested in a library board consisting of five members who shall be appointed by the county commission or the governing body of the municipality. The terms of membership on the library board, as first appointed, for one member shall be for one year, for the second member shall be for two years, for the third member shall be for three years, and for the remaining two members the terms shall be for four years. After the first term, all appointments shall be for four years. The county commission or governing body shall fill all vacancies including expired and unexpired terms. Members of the library board shall serve without compensation.