Help with Camera relative Movements

I’m a beginner and asking on How will i be able to put the Camera relative controls in my current Codes.

thank you for all the help.

using UnityEngine;
using System.Collections;

public class Movements3 : MonoBehaviour {

public Camera _camera;

public float moveSpeed = 5.0f;
public float jumpSpeed = 5.0f;
private CharacterController Player;
public float gravity = 10.0f;
private float fallSpeed;

private bool isGrounded;

// Use this for initialization
void Start () {
    Player = GetComponent<CharacterController>();

}

// Update is called once per frame
void Update () {
    IsGrounded();
    Fall();
    Jump();
    Move();
}

void Move()
{
    // Vector3 forward = _camera.transform.TransformDirection(Vector3.forward);
    float xSpeed = Input.GetAxis("Horizontal");
    if (xSpeed != 0) Player.Move(new Vector3(xSpeed, 0) * moveSpeed * Time.deltaTime);
}

void Jump()
{
    if (Input.GetButtonDown("Jump") && isGrounded)
    {
        fallSpeed = -jumpSpeed;
    }
}

void Fall()
{
     if (!isGrounded)
    {
        fallSpeed += gravity * Time.deltaTime;
    } else
    {
        if (fallSpeed > 0) fallSpeed = 0;
    }
    Player.Move(new Vector3(0, -fallSpeed) * Time.deltaTime);

}

void IsGrounded()
{
    isGrounded = (Physics.Raycast(transform.position, -transform.up,0));
}

}

You have the right idea about setting the forward direction with your comment in the code. To make it so that the input is actually relative to the camera, you need to use the orientation of your camera to adjust your input. Here is the code I use to do my movement setting:

//GET THE CAMERAS ORIENTATION
Vector3 forward = myCamera.transform.TransformDirection (Vector3.forward);
forward.Normalize ();
Vector3 right = new Vector3 (forward.z, 0, -forward.x);

//SET DIRECTION
moveDirection = (inputH * right + inputV * forward);