Welcome back! :thumbsup:
The problem here is conceptual: what is an Objective? Last time I looked this was not well covered in the tutes - there's lots of technical stuff on how to make the green tick appear, but very little on the fundamentals.
An Objective
- is something the player must do to complete the mission
- normally has a line in the Briefing which gets a green tick when the player has done it
- is normally associated with one or more triggers in the mission that must be fired for the Objective to be completed
You can of course have triggers in a mission that can only be fired by the player but which have nothing to do (directly) with an Objective.
You can also have Objectives that never appear in the Briefing, although in that case you have to be very careful to ensure that the player can figure out what he is supposed to do and how he will know when he has done it.
Sometimes Objectives are optional, the player doesn't have to do them. Sometimes they are hidden at the start of the mission, and occasionaly - too occasionally - they are conditional, so that completing or failing the first one makes subsequent ones appear or disappear.
And of course it doesn't always have to be a trigger: occasionally it's a script, waypoint (an AI waypoint, not a player one) or something else.
Hope that helps.