Actions On is a military term, used in orders briefings, to designate the correct action upon a specific event.
For instance;
Actions On lost: Walk until you encounter a road. Ignite your Cyalume (glow stick), put on warm layers, and await collection.
For obvious reasons, these actions on cannot remain constant for all exercises and operations- some areas may be too large to use "Walk until you encounter a road", and in some circumstances "Ignite Cyalume and wait" might endanger a soldier as they are more likely to encounter the enemy that friendly troops. It is for this reason that Actions On differ from regular drills. Whereas a drill is a constant, Actions On can change.
Actions On lost: Take cover in tree line, establish co-ordinates from GPS and radio them to Section Commander. If this fails, wait until day-light and use visual aids to establish position.
The above may be more appropriate if the required equipment is possessed.