Making AI attack (My Script Attached)

Hello I'm trying to make my AI attack me and take damage off me. My script is below. Where would I begin in making this happen.

EnemyAtk.js

 var giveUpThreshold = 20; // distance beyond which AI gives up
 var attackRepeatTime = 1; // delay between attacks when within range
  
 private var chasing = false;
 private var attackTime = Time.time;
  
 var myTransform : Transform; //current transform data of this enemy
  
 function Awake()
 {
     myTransform = transform; //cache transform data for easy access/preformance
 }
  
 function Start()
 {
      target = GameObject.FindWithTag("Player").transform; //target the player
 }
  
 function Update () {
  
     // check distance to target every frame:
     var distance = (target.position - myTransform.position).magnitude;
  
     if (chasing) {
  
         //rotate to look at the player
         myTransform.rotation = Quaternion.Slerp(myTransform.rotation,
         Quaternion.LookRotation(target.position - myTransform.position), rotationSpeed*Time.deltaTime);
  
         //move towards the player
         myTransform.position += myTransform.forward * moveSpeed * Time.deltaTime;
  
         // give up, if too far away from target:
         if (distance > giveUpThreshold) {
             chasing = false;
         }
  
         // attack, if close enough, and if time is OK:
         if (distance < attackThreshold && Time.time > attackTime) {
             // Attack! (call whatever attack function you like here)
 
             attackTime = Time.time + attackRepeatTime;
         }
    
     } 
     
     else {
         // not currently chasing.
  
         // start chasing if target comes close enough
         if (distance < chaseThreshold) {
             chasing = true;
         }
     }
 }

and my player Health Script is attached below.

 // JavaScript
 var enemyHealth : int = 100;
 var backgroundTexture : Texture;
 var foregroundTexture : Texture;
 var frameTexture : Texture;
 
 var healthWidth: int = 199;
 var healthHeight: int = 30;
 
 var healthMarginLeft: int = 41;
 var healthMarginTop: int = 38;
 
 var frameWidth : int = 266;
 var frameHeight: int = 65;
 
 var frameMarginLeft : int = 10;
 var frameMarginTop: int = 10;
 
 function OnGUI () {
 
     GUI.DrawTexture( Rect(frameMarginLeft,frameMarginTop, frameMarginLeft + frameWidth, frameMarginTop + frameHeight), backgroundTexture, ScaleMode.ScaleToFit, true, 0 );
     
     GUI.DrawTexture( Rect(healthMarginLeft,healthMarginTop,healthWidth + healthMarginLeft, healthHeight), foregroundTexture, ScaleMode.ScaleAndCrop, true, 0 );
     
     GUI.DrawTexture( Rect(frameMarginLeft,frameMarginTop, frameMarginLeft + frameWidth,frameMarginTop + frameHeight), frameTexture, ScaleMode.ScaleToFit, true, 0 );
 
 }

I was thinking of adding something to do with the collision to the enemy's attack script but I've only just started learning coding and not sure about how I would code it, I know the idea of what I want to do like Collision>Enemy=attack>player health goes down -3 but how would I make that happen and what sort of tutorial will help me?