You can set up to 10 attack points per enemy.
For an attack point you set:
the radius, that is the area that is attacked
the interval
the moment of the first attack (the time from map start to first attack)
The actual time depends on the play speed (1, 2 or 3). With speed 3, the enemies attack much earlier than with speed 1.
With the attack points you can influence how many enemies attack.
The distance also plays a role, that is, how far the attack point is situated from the enemy's barracks.