(a) A decision or order adverse to a party who appeared and participated in a hearing must be in writing and include separately stated findings of fact and conclusions of law on the issues material to the decision or order. Findings of fact that are stated in statutory language must be accompanied by a concise and explicit statement of the underlying facts supporting the findings.
(b) A decision or order entered after a hearing is final and appealable on the 15th day after the date it is entered unless a party files a motion for rehearing before that date. If the motion for rehearing is overruled, a decision or order is appealable after the date an order overruling a motion for rehearing is entered.

(c) Each party to a hearing shall be promptly notified personally or by mail of a decision, order, or other action taken in respect to the subject matter of the hearing.