I would like to know if this script is correct for the movement of a player?

Unity Engine
, ,
1 
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class SimpleMovement : MonoBehaviour
{

    //Cancellare start
    //dichiaro le variabili
    public float movementSpeed = 5f;
  


    void Update()
    {
        if (Input.GetKey(KeyCode.UpArrow))
        {
            transform.Translate(Vector3.forward * movementSpeed * Time.deltaTime);
        }
        if (Input.GetKey(KeyCode.DownArrow))
        {
            transform.Translate(-Vector3.forward * movementSpeed * Time.deltaTime);
        }

        if (Input.GetKey(KeyCode.RightArrow))
        {
            transform.Translate(Vector3.right * movementSpeed * Time.deltaTime);
        }
        if (Input.GetKey(KeyCode.LeftArrow))
        {
            transform.Translate(-Vector3.right * movementSpeed * Time.deltaTime);
        }
    }
}
2

I dunno, does it work?

4 
using UnityEngine;

public class PlayerController : MonoBehaviour
{
    public float speed; //your speed value here.
    public float sidewaysSpeed; //your sideways Speed value here.
    
    void Update()
    {
        float horizontalInput = Input.GetAxis("Horizontal"); //GetAxis("[horizontal/vertical here]") is like a slider for vertical and horizontal going from -1 to 1.
        //thisway you dont have to get the different arrow keys and best of all, it also should work with wasd.
        float verticalInput = Input.GetAxis("Vertical");

        transform.Translate(Vector3.forward * speed * verticalInput * Time.deltaTime);
        transform.Translate(Vector3.right * sidewaysSpeed * horizontalInput * Time.deltaTime); //with this code, you only have to write transform.Translate two times and you can even adjust the speed for horizontal and vertical movement individually.
    }
}

Let me know if something is unclear or you need assistance with anything else.
There are also a lot of tutorials on YouTube about all the different ways to make a PlayerController.