How to make my cards dragable in my solitaire game?

Hi im making a solitaire game but i dont know how to make my cards dragable

using UnityEngine;
using System.Collections;

public class SetupCards : MonoBehaviour 
{
    int numberOfCards = 52;
    int numberOfCardSorts = 4;
    public float verticalSize = 1.4f;

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

    // Update is called once per frame
    void Update() 
    {
        
	}

    void OnGUI()
    {
        int currentSort = 0;
        int cardNumber = 0;

        for (int i = 0; i < numberOfCards; ++i)
        {
            int numberOfCardsPerSort = numberOfCards / numberOfCardSorts;
            float cardSizeX = Screen.width / numberOfCardsPerSort;

            if (cardNumber == numberOfCardsPerSort)
            {
                ++currentSort;
                cardNumber = 0;
            }

            Vector2 cardSize = new Vector2(cardSizeX, cardSizeX * verticalSize);

            Rect rect = new Rect(
                cardSize.x * cardNumber,
                cardSize.y * currentSort,
                cardSize.x,
                cardSize.y);

            string texturePath = "Textures/cards/";

            switch (currentSort)
            {
                case 0:
                    texturePath += "diamond/diamond_";
                    break;

                case 1:
                    texturePath += "clover/clover_";
                    break;

                case 2:
                    texturePath += "heart/heart_";
                    break;

                case 3:
                    texturePath += "spade/spade_";
                    break;
            }

            texturePath += cardNumber.ToString();

            //Debug.Log(texturePath);

            Texture texture = Resources.Load(texturePath) as Texture;

            GUI.Label(rect, texture);

            ++cardNumber;
        }
    }
}

You can also make them rigidbodies with a colliders and on the camera add the Drag Rigidbody script, it’s a default Unity script, so no writing needed.