(a) During the thirty days next preceding an election, the county election board shall place on public exhibition, in such public places, and at such times as it may deem most suitable for the information and instruction of the voters, one or more voting machines, containing the ballot labels, and showing the offices and questions to be voted upon, the names and arrangements of parties, and, so far as practicable, the names and arrangements of the candidates to be voted for. Such machine or machines shall be under the charge and care of a person competent as custodian and instructor. No voting machine, which is to be assigned for use in an election, shall be used for such public exhibition and instruction, after having been prepared and sealed for the election.

(b) During such public exhibition and instruction, the counting mechanism of the voting machine shall be concealed from view, and the doors, or cover concealing the same, shall be opened, if at all, only temporarily, and only upon written authorization from the county election board.

(c) Prior to any election, the county board may cause copies of any diagram or diagrams, required to be furnished with voting machines at polling places, to be made, either in full size or in reduced size, and to be posted, published, advertised or distributed among the electors in such manner as they may deem desirable.