Mass. Gen. Laws ch. 53 § 118
The notice for a caucus under the preceding section shall be written or printed, shall state the place where, and the day and hour when, said caucus is to be held, shall be issued at least seven days prior thereto, and shall be conspicuously posted in at least five places on lines of public travel, and, if practicable, in every post office within the city or town, or shall be published at least twice in one or more local newspapers. Said notice shall be signed by one or more voters of the ward, town or district for which the caucus is called, and shall designate by name or office the person who shall call such caucus to order, and he shall preside until a chairman is chosen. In his absence, the caucus may choose a temporary chairman. The first business in order shall be the organization of the caucus by the choice of a chairman, a secretary, and such other officers as the meeting may require. The persons receiving the highest number of votes shall be declared elected or nominated. The caucus may adopt regulations consistent with law.
Mass. Gen. Laws ch. 53, § 118