How do I add a run mechanic to this script

using System;
using UnityEngine;

namespace UnityStandardAssets._2D
{
public class PlatformerCharacter2D : MonoBehaviour
{
[SerializeField] private float m_MaxSpeed = 10f; // The fastest the player can travel in the x axis.
[SerializeField] private float m_JumpForce = 400f; // Amount of force added when the player jumps.
[Range(0, 1)] [SerializeField] private float m_CrouchSpeed = .36f; // Amount of maxSpeed applied to crouching movement. 1 = 100%
[SerializeField] private bool m_AirControl = false; // Whether or not a player can steer while jumping;
[SerializeField] private LayerMask m_WhatIsGround; // A mask determining what is ground to the character

private Transform m_GroundCheck; // A position marking where to check if the player is grounded.
const float k_GroundedRadius = .2f; // Radius of the overlap circle to determine if grounded
private bool m_Grounded; // Whether or not the player is grounded.
private Transform m_CeilingCheck; // A position marking where to check for ceilings
const float k_CeilingRadius = .01f; // Radius of the overlap circle to determine if the player can stand up
private Animator m_Anim; // Reference to the player's animator component.
private Rigidbody2D m_Rigidbody2D;
private bool m_FacingRight = true; // For determining which way the player is currently facing.

private void Awake()
{
// Setting up references.
m_GroundCheck = transform.Find("GroundCheck");
m_CeilingCheck = transform.Find("CeilingCheck");
m_Anim = GetComponent<Animator>();
m_Rigidbody2D = GetComponent<Rigidbody2D>();
}


private void FixedUpdate()
{
m_Grounded = false;

// The player is grounded if a circlecast to the groundcheck position hits anything designated as ground
// This can be done using layers instead but Sample Assets will not overwrite your project settings.
Collider2D[] colliders = Physics2D.OverlapCircleAll(m_GroundCheck.position, k_GroundedRadius, m_WhatIsGround);
for (int i = 0; i < colliders.Length; i++)
{
if (colliders.gameObject != gameObject)
m_Grounded = true;
}
m_Anim.SetBool("Ground", m_Grounded);

// Set the vertical animation
m_Anim.SetFloat("vSpeed", m_Rigidbody2D.velocity.y);
}


public void Move(float move, bool crouch, bool jump)
{
// If crouching, check to see if the character can stand up
if (!crouch && m_Anim.GetBool("Crouch"))
{
// If the character has a ceiling preventing them from standing up, keep them crouching
if (Physics2D.OverlapCircle(m_CeilingCheck.position, k_CeilingRadius, m_WhatIsGround))
{
crouch = true;
}
}

// Set whether or not the character is crouching in the animator
m_Anim.SetBool("Crouch", crouch);

//only control the player if grounded or airControl is turned on
if (m_Grounded || m_AirControl)
{
// Reduce the speed if crouching by the crouchSpeed multiplier
move = (crouch ? move*m_CrouchSpeed : move);

// The Speed animator parameter is set to the absolute value of the horizontal input.
m_Anim.SetFloat("Speed", Mathf.Abs(move));

// Move the character
m_Rigidbody2D.velocity = new Vector2(move*m_MaxSpeed, m_Rigidbody2D.velocity.y);

// If the input is moving the player right and the player is facing left...
if (move > 0 && !m_FacingRight)
{
// ... flip the player.
Flip();
}
// Otherwise if the input is moving the player left and the player is facing right...
else if (move < 0 && m_FacingRight)
{
// ... flip the player.
Flip();
}
}
// If the player should jump...
if (m_Grounded && jump && m_Anim.GetBool("Ground"))
{
// Add a vertical force to the player.
m_Grounded = false;
m_Anim.SetBool("Ground", false);
m_Rigidbody2D.AddForce(new Vector2(0f, m_JumpForce));
}
}


private void Flip()
{
// Switch the way the player is labelled as facing.
m_FacingRight = !m_FacingRight;

// Multiply the player's x local scale by -1.
Vector3 theScale = transform.localScale;
theScale.x *= -1;
transform.localScale = theScale;
}
}
}

 

Take a look at the Platformer2DUserControl script. In the FixedUpdate() of the Platformer2DUserControl script, they call PlatformerCharacter2D's Move() method, which sets the rigidbody2d's velocity to move*m_MaxSpeed. If you don't need the crouch functionality, just pass in false as the second parameter.

 

I would just use a simple if statement and a key press if key pressed run = true; if run == true do // run code end else walk code