All managers of election for the various polling places in the State must be residents and registered electors of the respective counties in which they are appointed to work or in an adjoining county. Any person at least sixteen years of age who has completed the training required by Section 7-13-72 and who is not otherwise disqualified by law may be appointed as a poll manager's assistant by the appropriate county election commission. Sixteen and seventeen-year-olds appointed as poll manager's assistants may not serve as chairman of the managers or clerk in the polling place to which they are appointed. They must serve under supervision of the chairman of the managers of the polling place and their specific duties must be prescribed by the county election commission. No polling place in this State may employ more than one sixteen or seventeen-year-old assistant poll manager.