Rules of the Game

Rule 11 - Teeing Ground
When a player is putting a ball into play from the teeing
ground, it must be played from within the teeing ground and
from the surface of the ground or from a conforming tee in or
on the surface of the ground.
For the purposes of this Rule, the surface of the ground
includes an irregularity of surface (whether or not created by
the player) and sand or other natural substance (whether or
not placed by the player).
Basically, this means to tee the ball up between the markers on what is the tee box. The Tee box actually encompasses the area between the two markers and up to two club length's behind the marker (making a box)