How to make a cube move in unity code example

Example: How to make a cube move in unity

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

public class Test : MonoBehaviour
{

    Rigidbody rb;
    Vector3 Vec;

    // Start is called before the first frame update
    void Start()
    {
        rb = GetComponent();
    }

    // Update is called once per frame
    void Update()
    {
        if(Input.GetKeyDown(KeyCode.Space))
        {
            rb.AddForce(Vector3.up * 500f);
        }

        Vec = transform.localPosition;
        Vec.y += Input.GetAxis("Jump") * Time.deltaTime * 20;
        Vec.x += Input.GetAxis("Horizontal") * Time.deltaTime * 20;
        Vec.z += Input.GetAxis("Vertical") * Time.deltaTime * 20;
        transform.localPosition = Vec;
    }
}