How do I enable the Nav Mesh obstacles on enemy ai in my scene for avoidance in the scene

I need to enable the nav mesh obstacles on my enemy ai and set the destination in the script as well . I declare nav mesh as a variable already . I need help with the rest . Here is my script :

 using UnityEngine;
  using System.Collections;
  
   public class Enemyai : MonoBehaviour {
   public Transform Player;
   Animator anim;
   public NavMeshObstacle nav;
       void Start () 
       {
               anim = GetComponent<Animator> ();
       }
       
       public void Stop(){
       anim.SetBool("isMove", false);
       anim.SetBool("isAttacking", false);
       anim.SetBool("isIdling", true);
       this.enabled = false;
       //Or if you want to destroy the AI script completely
       //Destroy(this)
   }
  
 
   
       void Update () 
       {
          
         float speed = 0.9f;
       if (Vector3.Distance(Player.position, this.transform.position) < 10000f)
           {
               nav = GetComponent <NavMeshObstacle> ();
               nav.SetDestination (Player.position);
               Vector3 direction = Player.position - this.transform.position;
               direction.y = 0;
               this.transform.rotation = Quaternion.Slerp (this.transform.rotation,Quaternion.LookRotation(direction), 0.1f);
               
               anim.SetBool("isIdling",false);
               if(direction.magnitude > 2 )
               {
 
 
                   this.transform.Translate(0,0,0.15f);
                   anim.SetBool("isMove",true);
                   anim.SetBool("isAttacking",false);
                   }
               else
               {
                   anim.SetBool("isAttacking",true);
                   anim.SetBool("isMove",false);
                   
               }
           }
          else
          {
              anim.SetBool("isIdling",true);
              anim.SetBool("isMove",false);
              anim.SetBool("isAttacking",false);
              
          }
       
  }
 
       
  }