As soon as practicable after the election, if a majority of the votes cast be in favor of establishing such district, the commissioners shall meet and organize as the board of commissioners of such special police district and they shall draw, by lot, the commissioners who shall hold office for the two, four and six year terms respectively. At the organization meeting and following the election of any commissioner thereafter they shall elect one of their number as chairman and another as secretary who shall keep a record of the deliberations of the board. In the event of any vacancy on the commission the remaining members of the commission shall elect a commissioner to fill the unexpired term. They shall serve without compensation.