Creating a "story" for a Character

Extremely new to scripting and don't even know what I need to look for in this question or if formulated correctly.

I have a 2D top down game and there are several NPCs that have their daily routine. What I want to do is find the best way to write their daily routine and how they will deal with the Player character or any other issues.

My ideas was to create several functions that allow to do basic actions (Go to, Open, etc) and write them almost like a movie script. My issue is understanding how it all works and how I can get a sequence of actions and reactions in the best way possible.

This is what I have so far:

 function Update () {
     
     //First action is to move to the Fridge
     GoToObject(objManager.objFridge);
 
     //Once arrived at the Fridge to Open the Door
     if (ArriveAtObject == true){
         OpenObject(objManager.objFridge);
     }
     else{
     }
 
 }
 
 function GoToObject (target : Obj_Properties){
     selectedObject = target;
     GetComponent(NavMeshAgent).destination = target.transform.position;
     isGoingToSelectedObject = true;
     
 
 }
 
 function ArriveAtObject (){
     // Detects if the actor arrives at the SELECTED OBJECT PIVOT
     if ((transform.position - selectedObject.transform.position).sqrMagnitude <= (transform.position * percentageDifferenceAllowed).sqrMagnitude){
         actorAtSelectedObjectPivot = true;
     }
     else {
         actorAtSelectedObjectPivot = false;
     }
 
     //once actor arrives at the destinationObj
     if(isGoingToSelectedObject && actorAtSelectedObjectPivot){
         isGoingToSelectedObject = false;
         actorAtSelectedObjectPivot = false;
         GetComponent(NavMeshAgent).destination = transform.position;
         return true;
         
     }
     else {
         return false;
         
     }
 }
 
 
 function OpenObject (target : Obj_Properties){
     target.objIsOpen = true;
 }

I was hoping I would just write action after action as functions with If statements and have a kind of AI behaviour. But in this example the actor won't even open the Fridge door.

I also attempted to just write this as one big function on the Update but once I add too many actions things start not to work that well and it becomes extremely messy if I want some branching based on player actions.

 function WifeFirstDay (){
 // Calculate a path between the player and the object
     var targetPath : NavMeshPath = NavMeshPath ();                                            //Name of the path calculated
     var possiblePath = GetComponent(NavMeshAgent).CalculatePath(targetPosition, targetPath);// Is a path possible between player and object?
 
 
 
 ///////////            SCRIPT START            ///////////////
     //actor wants to go to the Fridge
     selectedObject = objManager.objFridge;
     GetComponent(NavMeshAgent).destination = selectedObject.transform.position;
     isGoingToSelectedObject = true;
     
     //once actor arrives at the Fridge
     if(isGoingToSelectedObject && actorAtSelectedObjectPivot){
         selectedObject.objIsOpen = true;
         isGoingToSelectedObject = false;
         actorAtSelectedObjectPivot = false;
         
         //Find if there is milk in the fridge:
         for (var child : Transform in selectedObject.transform) {
             if (child.gameObject.name == "Obj_Milk"){
                 var inventoryObject = child.gameObject;
                 inventoryObject.transform.parent = transform;
             }
             else {
             inventoryObject = null;
             }
         }
     }
     
     yield WaitForSeconds (3);
     
     //Result if the actor found milk or not.
     if (inventoryObject.name == "Obj_Milk"){
         selectedObject.objIsOpen = false;
         selectedObject = objManager.objKitchenTable;
         GetComponent(NavMeshAgent).destination = selectedObject.transform.position;
         isGoingToSelectedObject = true;
     }
     else if (inventoryObject == null){
         print("Where is the milk?");
         
         /*
         FindActor("PLAYER");
         if (FindActor){
             //ask where is the milk.
         }
         else {
             //go back to bedroom
         }
         */
     }