Convert Keyboard controlls to UI Buttons

using UnityEngine; using System.Collections;

public class PlayerController : MonoBehaviour {

 public float maxSpeed = 6f;
 public float jumpForce = 1000f;
 public Transform groundCheck;
 public LayerMask whatIsGround;
 public float verticalSpeed = 20;
 [HideInInspector]
 public bool lookingRight = true;
 bool doubleJump = false;
 public GameObject Boost;
 
 private Animator cloudanim;
 public GameObject Cloud;


 private Rigidbody2D rb2d;
 private Animator anim;
 private bool isGrounded = false;


 // Use this for initialization
 void Start () {
     rb2d = GetComponent<Rigidbody2D>();
     anim = GetComponent<Animator>();
     //cloudanim = GetComponent<Animator>();

     Cloud = GameObject.Find("Cloud");
       //cloudanim = GameObject.Find("Cloud(Clone)").GetComponent<Animator>();
 }


 void OnCollisionEnter2D(Collision2D collision2D) {
     
     if (collision2D.relativeVelocity.magnitude > 20){
         Boost = Instantiate(Resources.Load("Prefabs/Cloud"), transform.position, transform.rotation) as GameObject;
     //    cloudanim.Play("cloud");    

     }
 }


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

 if (Input.GetButtonDown("Jump") && (isGrounded || !doubleJump))
     {
         rb2d.AddForce(new Vector2(0,jumpForce));

         if (!doubleJump && !isGrounded)
         {
             doubleJump = true;
             Boost = Instantiate(Resources.Load("Prefabs/Cloud"), transform.position, transform.rotation) as GameObject;
         //    cloudanim.Play("cloud");        
         }
     }


 if (Input.GetButtonDown("Vertical") && !isGrounded)
     {
         rb2d.AddForce(new Vector2(0,-jumpForce));
         Boost = Instantiate(Resources.Load("Prefabs/Cloud"), transform.position, transform.rotation) as GameObject;
         //cloudanim.Play("cloud");
     }

 }


 void FixedUpdate()
 {
     if (isGrounded) 
         doubleJump = false;


     float hor = Input.GetAxis ("Horizontal");

     anim.SetFloat ("Speed", Mathf.Abs (hor));

     rb2d.velocity = new Vector2 (hor * maxSpeed, rb2d.velocity.y);
       
     isGrounded = Physics2D.OverlapCircle (groundCheck.position, 0.15F, whatIsGround);

     anim.SetBool ("IsGrounded", isGrounded);

     if ((hor > 0 && !lookingRight)||(hor < 0 && lookingRight))
         Flip ();
      
     anim.SetFloat ("vSpeed", GetComponent<Rigidbody2D>().velocity.y);
 }


 
 public void Flip()
 {
     lookingRight = !lookingRight;
     Vector3 myScale = transform.localScale;
     myScale.x *= -1;
     transform.localScale = myScale;
 }

}