Warning orders are the "5 W's of an events"  all the basic questions are answered in this 1 document. All events have a warning order, most you will find published here as they become available.

Definition: (NATO) 1. A preliminary notice of an order or action which is to follow. 2. A planning directive that describes the situation, allocates forces and resources, establishes command relationships, provides other initial planning guidance, and initiates subordinate unit mission planning.