Notice of hearing shall be given not less than 10 days before such hearing is held unless the parties agree to a shorter notice period. Such notice shall be transmitted to the labor organization and the officer(s) accused of misconduct and other interested persons, insofar as they are known, and shall inform them of:

(a) The time, place, and nature of the hearings;

(b) The legal authority and jurisdiction under which the hearing is to be held; and

(c) The matters of fact and law asserted.