There are several things a sentry must know in order to perform their role:

1. Locations of:
   • Neighbouring posts;
   • Own backup; and
   • Covering sentries.
2. Length of time of duty and what time it will start.
3. Method of relief.
   • Who is taking over from you; and
   • How will they know?
4. Situation of enemy forces.
5. Arcs of observation.
6. Arcs of fire.
7. Location of mines, trip flares and other local defences.
8. Action on suspicious movement.
9. Method of alerting troops.
10. Method of challenging.
    • Procedure on hearing correct password.
    • Procedure on hearing incorrect password.
11. Orders for opening fire.
12. Information on friendly patrols coming in or going out.
13. Concealment (of own position).
14. Questions (you as the sentry may wish to ask).
15. Password:
    • Current password; and
    • If changing, new password and time of change.

The first person posted as a sentry will draw a sketch of the surrounding area noting buildings, dead ground, arcs of fire among other details.

A sentry will also provide passive reconnaissance, logging the movement of people and vehicles.