(a) In addition to other requirements imposed by law, each agency shall:
(1) Adopt and make available for public inspection a description of its organization, stating the general course and method of its operations and the methods whereby the public may obtain information or make submissions or requests;
(2) Adopt and make available for public inspection a written policy statement setting forth the nature and requirements of all formal and informal procedures available, including a description of all forms and instructions used by the agency;
(3) Make available for public inspection all final orders, decisions and opinions except as otherwise provided by law.
(b) No agency rule, order or decision is valid or effective against any person or party, nor may it be invoked by the agency for any purpose until it has been made available for public inspection as required by this article and Article 2. This provision is not applicable in favor of any person or party who has actual knowledge thereof.