Game Combat

Hello, I'm currently a first year student at college studying Computer Science. I have a project/game that I almost managed to complete, but I'm struggling to figure out how to implement combat. I tried searching the browser for answers, however the outcome was unsuccessful. I even looked at a handful of YouTube videos, which did help me with sections of the combat such as making the enemy follow the player, but I couldn't quite get them to interact and take damage from each other. I'm running out of time and ideas of how to solve this problem so I though I would get some advice from here.

• I need the player to take some health from the enemy once the enemy appears on screen (and the required input has been given). Here's the player code so far:

     if (Input.GetMouseButtonDown(1))
                   {
                       //When enemy is facing player attack
                       var forward = transform.TransformDirection(Vector3.forward);
                       var distance = Vector3.Distance(transform.position, enemy.position);
                       var targetDirection = enemy.position - transform.position;
                       targetDirection.y = 0;
                       var angle = Vector3.Angle(targetDirection, forward);
   
               if (distance < attackRange && angle < spotAngle)
               {
                   TakeDamage.Enemy(20); //Attack();
               }
   
               Ray ray = cam.ScreenPointToRay(Input.mousePosition);
               RaycastHit hit;
   
               if(Physics.Raycast(ray, out hit, 100))
               {
                   Interactable interactable = hit.collider.GetComponent<Interactable>();
                   if(interactable != null)
                   {
                       SetFocus(interactable);
                   }
               }
           }
  
  

• I also need the enemy to take some health from the player once they collide.

Here's the enemy code for the collision: public float initialHealth = 60f; private float currentHealth;

 void Start()
 {
     currentHealth = initialHealth;
 }

 public void TakeDamage(float damage)
 {
     currentHealth -= damage;

     if (currentHealth < 0)
     {
         Destroy(gameObject);
     }
 }

 public override void Interact()
 {
     base.Interact();
 }

 void OnCollisonEnter(Collision collision)
 {
     if (collision.collider.gameObject.Player.CompareTag("Enemy"))
     {
         TakeDamage(20);
     }
 }

I know this is a lot to ask for, but I really don't know what to do at this point.