Access Array inside ArrayList()

hi, i have a problem to access an Array insede an ArrayList, in this the code(c#) :

 public void getWaypoints() {
         ArrayList potentialWPs = new ArrayList();
         potentialWPs.Add(containerWaypoint.GetComponentInChildren(typeof(Transform)));
         wayPoints = new ArrayList();
 
         foreach (Transform potentialWP in potentialWPs){
             if(potentialWP.transform != containerWaypoint.transform){
                 wayPoints[wayPoints.Count] = new ArrayList(2);
                 wayPoints[wayPoints.Count][0] = potentialWP;
 
             
             }
         }

i want to access the array inseide each ArrayList's elements, but its says that "cannot aplly indexing with[] to an expression of type 'object'" to line "wayPoints[wayPoints.Count][0]", anyone knows how to solve it..??

thanks for the help n sorry for my bad english....