Can't get ground units to fire at the ground

[Gunfreak]

I've tried to follow this goolge AI thing

 

Here is the step-by-step process to set it up:

1. Place the Units: Add your vehicles or artillery to the map via the Group or Vehicle/Artillery tabs.
2. Add the Attack Command: Go to the MCU tab, select Command, and place a Attack Area MCU near your ground units. [1, 2, 3]
3. Set the Target Parameters: Double-click the Attack Area MCU to open its properties.
   • Check the box for Attack Ground.
   • Adjust the Radius setting to determine how large of an area the units should target. [1, 2, 3]
4. Link the Logic:
   • Target Link (red) from an activation source (e.g., a Translator: Mission Begin or a Timer) to the Attack Area MCU.
   • Object Link (blue) from the Attack Area MCU directly to your ground unit(s) or vehicle group. [1, 2]

I've also tried to add an activate trigger, but that has no effect, the ground units don't fire