i need help removing an error in my targetting/attack script

ive made this script and have had a bit of help but now i seem to get and error

and if you can help me set it to target the closest target(Enemy)/deselect when selecting new targget(Enemy) id be forever grateful :)

Assets/_Scripts/random scripts/PlayerAttack.cs(17,54): error CS0029: Cannot implicitly convert type UnityEngine.GameObject[]' to System.Collections.Generic.List'

/// /// PlayerAttack.cs /// /// This is a basic attack script to get us use to usng C# and Unity /// /// Attach ths script to your player /// using UnityEngine; using System.Collections; using System.Collections.Generic;

public class PlayerAttack : MonoBehaviour { public GameObject target; public float attackTimer; public float coolDown;

 List<GameObject> AllEnemiesList = GameObject.FindGameObjectsWithTag("Enemy"); 
 List<GameObject> VisibleEnemiesList = new List<GameObject>();


 // Use this for initialization
 void Start () {
     attackTimer = 0;
     coolDown = 2.0f;
     
     foreach (Transform Enemy in EnemiesList) {
 if (Enemy.GameObject.renderer.IsVisibleFrom(Camera.main)) {
     VisibleEnemiesList.Add (Enemy.GameObject);
 }

} }

 // Update is called once per frame
 void Update () {
     if(attackTimer > 0)
         attackTimer -= Time.deltaTime;
     
     if(attackTimer < 0)
         attackTimer = 0;
     
     if(Input.GetKeyUp(KeyCode.Mouse0)) {
         if(attackTimer == 0) {
             Attack();
             attackTimer = coolDown;
             
             
         }
         if (Input.GetKey (KeyCode.Tab)) {
             TargetEnemy();

} }

 }
 
 private void Attack() {
     float distance = Vector3.Distance(target.transform.position, transform.position);
     
     Vector3 dir = (target.transform.position - transform.position).normalized;
     
     float direction = Vector3.Dot(dir, transform.forward);
     
     if(distance < 2.5f) {
         if(direction > 0) {
             EnemyHealth eh = (EnemyHealth)target.GetComponent("EnemyHealth");
             eh.AddjustCurrentHealth(-10);
         }
     }
 }

}