Within 20 days after the receipt of a notice of appeal, the director shall set a hearing date or, if no hearing is requested, a date for consideration of the appeal by the appeals board. The director shall serve upon all affected persons known to the director:

(1) A statement of the time, place and nature of the proceeding;

(2) A statement of the legal authority and jurisdiction under which the hearing is to be held;

(3) A reference to the particular sections of the statutes and rules involved;

(4) A short and plain statement of the matters asserted. If the agency or other party is unable to state the matters in detail at the time the notice is served, the initial notice may be limited to a statement of the issues involved. Thereafter upon request a more definite and detailed statement shall be furnished.