When the petition is approved by the clerk of court of the county in which the proposed special district is located the clerk shall call an election of the qualified voters within such district to vote upon the question of establishing the district for the purpose of special police protection. The clerk shall designate some place within the proposed district for the holding of the election and shall appoint the managers and declare the results thereof. He shall give notice of the time and place thereof for at least three weeks in some newspaper published in the county and by posting notices thereof in at least three public places within the proposed district for the same length of time. At such election only the qualified electors residing within the district shall be allowed to vote, according to the laws of general elections. They shall vote "Yes" or "No" on the question of establishing such special police district and at the same election they shall vote on the election of three commissioners to hold office, in the event a majority of the votes cast shall be in favor of establishing such district, for terms of two, four and six years and until their successors are elected and qualified, their successors, however, to have terms of office of six years and until their successors are elected and qualified. Thereafter a commissioner shall be elected at the time of each State biennial election.