Welcome to the fabled Spy Academy Files. Learn them, live them, love them. Then practice them. Experience in the field is the best learning experience.
Here's a quick legend to what the symbols on the pictures mean:
! - Watch this spot.
X - Sentry gun
R - Respawn room here
S - Sniper here
F - Flag here
==> - Go in this direction
Other symbols will be map specific. And described in the text.