This is a simple example of how to activate a waypoint using a trigger in Arma editor.
VIDEO EXAMPLE
* Create unit* Create 2 waypoints
- 1 waypoint must be close to unit so we can stop him
- 2 waypoint must be where you want your unit to go
* Create a trigger and synchronize it with first waypoint of the unit.
-You don't have to change anything in the trigger options!
And that's it...off he goes.