Multiple Objects in Wave Spawner?

Hello everyone, I was doing the Brackey's tutorial on wave spawner. It taught me how to have multiple waves & spawners but the things is, each wave can only spawn ONE type of enemy. I want to have an array of enemies that I can insert into each wave so that each wave can have multiple types of enemies spawning. Here's the code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class spawnerScript : MonoBehaviour
 {
 
 
     [System.Serializable]
     public class Wave
     {
         public string name;
         public Transform enemy;
         public int count;
         public float rate;
 
     }
 
     public enum SpawnState { SPAWNING, WAITING, COUNTING};
     public SpawnState state = SpawnState.COUNTING;
     public Wave[] waves;
     private int nextWave = 0;
 
     public float timeBetweenWaves = 5f;
     public float waveCountdown;
 
     private float searchCd = 1f;
 
     public Transform[] spawnPoints;
 
     void Start()
     {
         waveCountdown = timeBetweenWaves;
         if (spawnPoints.Length == 0)
             {
                 Debug.LogError("no spawn points");
             }
     }
     void Update()
     {
 
         if (state == SpawnState.WAITING)
         {
             if (!EnemyIsAlive())
             {
                 waveCompleted();
                 return;
             }
             else
             {
                 return;
             }
         }
 
         if (waveCountdown <= 0)
         {
             if(state != SpawnState.SPAWNING)
             {
                 StartCoroutine(SpawnWave(waves[nextWave]));
 
             }
         }
         else
         {
             waveCountdown -= Time.deltaTime;
 
         }
     }
 
 
         void waveCompleted()
         {
             Debug.Log("Wave Completed!!");
             state = SpawnState.COUNTING;
             waveCountdown = timeBetweenWaves;
 
             if (nextWave + 1 > waves.Length - 1)
             {
                 nextWave = 0;
                 Debug.Log("You won. Looping. Good luck.");
             }
             else
             {
             nextWave++;
 
             }
         }
     bool EnemyIsAlive()
     {
         searchCd -= Time.deltaTime;
         if (searchCd <= 0f)
         {
             searchCd = 1f;
 
         
             if (GameObject.FindGameObjectWithTag("Enemy") == null)
             {
             return false;
         
             }
         }
         return true;
     }
 
     IEnumerator SpawnWave(Wave wave)
     {
         Debug.Log("Spawning wave: "+ wave.name);
         state = SpawnState.SPAWNING;
         
 
 
         //SPAWN
 
         for (int i = 0; i <wave.count; i++)
         {
             SpawnEnemy(wave.enemy);
             yield return new WaitForSeconds(1f/wave.rate);
         }
         state = SpawnState.WAITING;
         yield break;
     }
 
     void SpawnEnemy(Transform _enemy)
     {        Debug.Log("Spawning "+ _enemy.name);
             
         Transform spawnP = spawnPoints[Random.Range(0, spawnPoints.Length)];
         Instantiate(_enemy, spawnP.position, Quaternion.identity);
     }
 }

I've never been too great at arrays, and I've been trying to get my head around this for hours. Thanks in advance.