Security Plan is a document that tells the security team "who, where, what and how". It not only solves incidents, but also routines: entrances, VIPs, corridors, closed areas, communication.
What it typically contains
- command structure (action commander, sector commanders),
- deployments and assignments,
- communication rules,
- scenarios: aggression, lost child, pyrotechnics, evacuation/invacuation.
It is the foundation without which a great action is governed by improvisation instead of a clear progression.
A detailed outline of roles, zones, communication and staffing can be found in the article Event Security Plan: A Practical Checklist for Organisers.