Create pushable and stackable objects

Hello i am new to unity and i wanted to create an object that is pushable. I did that using a ridigbody 2D. I want it if i stack the objects that if i push against the bottom one that all other object move as well.

This is what i tried:

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

public class MovableObject : MonoBehaviour
    private Rigidbody2D rb;
    private void Start()
        rb = GetComponent<Rigidbody2D>();

    private void OnTriggerStay2D(Collider2D other)
        Rigidbody2D otherRb = other.gameObject.GetComponent<Rigidbody2D>();

        otherRb.velocity += rb.velocity;

Currently only the bottom object has the script on it.