Guys i really need help with generating caves in terrain

I want to add Caves so if annyone could help me i really need it.


code:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class GenerateChunk : MonoBehaviour {
public GameObject grassBlock;
public GameObject dirtBlock;
public GameObject stoneBlock;
public int smoothnes;
public int additionalHight;
public float multiplayerHight;
public int width;
float seed;
public GameObject tileCoal;
public GameObject tileDiamond;
public GameObject tileGold;
public GameObject tileIron;
public GameObject tileSchwantz;
public GameObject tileLarp;
public GameObject tree;
public float chanceSchwantz;
public float chanceLarp;
public float chanceCoal;
public float chanceDiamond;
public float chanceGold;
public float chanceIron;
float treeCount;
// Use this for initialization
void Start () {
seed = Random.Range(-1000, 1000);
Generate();
}

void Generate()
{
for (int i = 0; i < width; i++)
{

int h = Mathf.RoundToInt(Mathf.PerlinNoise(seed, (i + transform.position.x) / smoothnes) * multiplayerHight) + additionalHight;
for (int j = 0; j < h; j++)
{
GameObject selectedTile;
if(j < h - 4 )
{
selectedTile = stoneBlock;
}
else if(j < h - 1 )
{
selectedTile = dirtBlock;
}
else
{
selectedTile = grassBlock;
}
GameObject newTile = Instantiate(selectedTile, Vector3.zero, Quaternion.identity) as GameObject;
if (treeCount < 4)
{
GameObject treeTile = Instantiate(tree, Vector3.zero, Quaternion.identity) as GameObject;
treeTile.transform.parent = this.gameObject.transform;
treeTile.transform.localPosition = new Vector3(i + Random.Range(0,65), h + Random.Range(3,4));

treeCount++;
}
newTile.transform.parent = this.gameObject.transform;
newTile.transform.localPosition = new Vector3(i, j);

}

}
Populate();
}
public void Populate()
{
foreach(GameObject t in GameObject.FindGameObjectsWithTag("Tile Stone"))
{
if(t.transform.parent = this.gameObject.transform)
{

float r = Random.Range(0f, 100f);
GameObject selectedTile = null;

if(chanceLarp > r )
{
selectedTile = tileLarp;
}

else if (chanceDiamond > r)
{

selectedTile = tileDiamond;
}
else if (chanceSchwantz > r)
{

selectedTile = tileSchwantz;
}
else if (chanceGold > r)
{
Debug.Log(r);
selectedTile = tileGold;
}
else if (chanceIron > r)
{
Debug.Log(r);
selectedTile = tileIron;
}
else if (chanceCoal > r)
{
Debug.Log(r);
selectedTile = tileCoal;
}
if (selectedTile != null)
{
GameObject NewResourceTile = Instantiate(selectedTile, t.transform.position, Quaternion.identity) as GameObject;
NewResourceTile.transform.parent = transform;
Destroy(t);
}
}
}
}
}