Unity 2d make four directions (Up, Down, Right, Left. like RPG games) GUI buttons. Please help me.

First of all, my English ability just a little. I made character and character movement. (Also made Animation, Animator. Four directions. like RPG games) I made to move the keyboard,

Up - keyboard "W" Down - keyboard "S" Right - keyboard "D" Left - keyboard "A"

made in t$$anonymous$$s format. (t$$anonymous$$s is a PlayerControllers Script) Format is created as a keyboard works well. But, How to create a GUI button, I do not know what to add, what to PlayerControllers Script. I found roughly, there is a movie that uses GetAxisRaw and Rigidbody2D... I do not know at all. Here are attached to PlayerControllers Script.

 using UnityEngine;
 using System.Collections;
 
 public class PlayerControllers: MonoBehaviour {
     
     public Animator anim;
     public float speed;
 
 
     // Use t$$anonymous$$s for initialization
     void Start () {
         anim = GetComponent<Animator> ();
     }
 
 
 
     // Update is called once per frame
     void Update () {
 
 
         if (Input.GetKey (KeyCode.D)) 
         {
             transform.Translate(Vector2.right * speed);
         }
         
         if (Input.GetKey (KeyCode.A)) 
         {
             transform.Translate(-Vector2.right * speed);
         }
         if (Input.GetKey (KeyCode.W)) 
         {
             transform.Translate(Vector2.up * speed);
         }
         if (Input.GetKey (KeyCode.S)) 
         {
             transform.Translate(-Vector2.up * speed);
         }
 
 
 
 
 
 
 
 
         
         if (Input.GetKey (KeyCode.A)) {
             anim.SetBool ("Left", true);
             anim.SetBool ("Right", false);
             anim.SetBool ("Up", false);
             anim.SetBool ("Down", false);
         }
         if (Input.GetKey (KeyCode.S)) {
             anim.SetBool ("Down", true);
             anim.SetBool ("Up", false);
             anim.SetBool ("Left", false);
             anim.SetBool ("Right", false);
             
         }
         if (Input.GetKey (KeyCode.D)) {
             anim.SetBool ("Right", true);
             anim.SetBool ("Left", false);
             anim.SetBool ("Up", false);
             anim.SetBool ("Down", false);
         }
         if (Input.GetKey (KeyCode.W)) {
             anim.SetBool ("Up", true);
             anim.SetBool ("Down", false);
             anim.SetBool ("Left", false);
             anim.SetBool ("Right", false);
         }
         
         
         
         if(Input.GetKey (KeyCode.A)){
             anim.SetBool("Player_Left", true);
         }
         else{
             anim.SetBool ("Player_Left", false);
         }
         
         
         
         if(Input.GetKey (KeyCode.S)){
             anim.SetBool("Player_Down", true);
         }
         else{
             anim.SetBool ("Player_Down", false);
         }
         
         
         
         if(Input.GetKey (KeyCode.D)){
             anim.SetBool("Player_Right", true);
         }
         else{
             anim.SetBool ("Player_Right", false);
         }
         
         
         
         if(Input.GetKey (KeyCode.W)){
             anim.SetBool("Player_Up", true);
         }
         else{
             anim.SetBool ("Player_Up", false);
         }
 
     }
 
 }
 

I would want to ask. To create a GUI button of the four directions and I want to move character to four directions (Up, Down, Right, Left), but it doesn't work. I do not know what to do in PlayerControllers Script added. What should i do to work t$$anonymous$$s corrcetly?

Also attach a Game Scene.

Please help me.

Thank you.