Foreach loop trying to grab all children in scene

Hello I have been working to try and figure this out for about 7 hours now(because I don’t have to programming experience) and can’t seem to get it.

My setup up is I have a gameobject that contains a pool of different objects(not active) that gets instantiated at run. I need to somehow find every object in the pool and randomly activate them at different times. Then move them to different spawn areas so they can do what they need to(i.e. move across the screen(I am working in 2D)). This is my script I have been messing with:

using UnityEngine;
using System.Collections;

public class SpawnPoolItems : MonoBehaviour {

	public Transform[] spawnPoints = new Transform[6];
	public float spawnMin = 1.0f;
	public float spawnMax = 2.0f;
	private GameObject[] prefabsToActivate;
	private GameObject[] items;
	private int randomActive;

	// Use this for initialization
	void Start () 
	{
		Spawn();
	}

	void Spawn()
	{
		foreach(Transform child in this.transform)
		{	
			child.gameObject.SetActive(true);
			/*for(int i = 0; i < items.Length; i++)
			{

			}
			*/
		}
		//Invoke("Spawn", Random.Range(SpawnMin, SpawnMax));
	}
}

I’ve tried multiple things with for and foreach loops but I keep getting errors and end up back at square one(which is where this script above sits). If anyone has any suggestions on how to do this please help I would be very grateful.

Here’s some code that works over time that should get you started:

public class EnableRandomChildren : MonoBehaviour
{
    // Keep a timer since the last time we "spawned" a child
    private float timeSinceLastSpawn;
     
    void Update()
    {
        // Tick down time until next spawn
        timeSinceLastSpawn += Time.deltaTime;

        // If the 2sec have passed for spawning
        if (timeSinceLastSpawn >= 2f)
        {
            // Schedule the next spawn in 2 sec
            timeSinceLastSpawn -= 2f;
            
            // Make a list of all children that are not yet enabled
            List<GameObject> availableObjects = new List<GameObject>();
            foreach (Transform child in transform)
                if (!child.gameObject.activeSelf)
                    availableObjects.Add(child.gameObject);

            // If we found some
            if (availableObjects.Count > 0)
            {
                // Choose a random child from the list
                GameObject childToEnable = availableObjects[Random.Range(0, availableObjects.Count)];
                // Enable the child
                childToEnable.SetActive(true);
                // .. and do other things to this child
            }
        }
    }
}