All elections shall be held prior to the first day of July. The retired school employee member shall be elected for a two- year term; the first term shall begin on the first day of July, one thousand nine hundred seventy-eight. All elections except those of the retired school employees, shall be for six-year terms; and all elective terms shall begin on the first day of July. The manner and mode of such elections shall be determined by the retirement board.
Vacancies occurring in the terms of the elected membership of the retirement board shall be filled within sixty days for unexpired periods by the retirement board. If the retirement board does not fill such vacancy within sixty days, the chairman shall appoint a member of the retirement system to serve for the remainder of the unexpired term.
Before exercising any authority or performing any duties as a member of the retirement board, each member shall qualify as such by taking and subscribing to the oath of office prescribed by section five, article four of the constitution, the certificates whereof shall be filed with the secretary of state.