PatrolBehaviour.cs

using UnityEngine;
using System.Collections.Generic;

public class PatrolBehaviour : MonoBehaviour {
  Queue<Transform> patrolTargets;
  
  void Start () {
    patrolTargets = new Queue<Transform>();
    patrolTargets.Enqueue(target1);
    patrolTargets.Enqueue(target2);
    // ... etc
  }
  
  void Update () {
    if (patrolTargets.Count > 0) {
      var target = patrolTargets.Peek();
      transform.position = Vector3.MoveTowards(transform.position, target.position, step);
      
      if (transform.position == target.position) {
        patrolTargets.Dequeue();
      }
    }
  }
}