how do i make first person character rotate left and right along with camera?

hello

im trying to get my first person character to only rotate left and right, using keyboard keys (A & D) because the character will be fixed in his position (so not move accross the map) and the player will be aiming and hsooting with the mouse.

currently, what the default script is doing is it moves him accross the map and jump etc...whil the mouse is the one that doe sthe rotation (in all directions...which is good, but i want left and right rotation with keyboard keys).

here is the scripts:

First Person Controller script:

 namespace UnityStandardAssets.Characters.FirstPerson
 {
     [RequireComponent(typeof (CharacterController))]
     [RequireComponent(typeof (AudioSource))]
     public class FirstPersonController : MonoBehaviour
     {
         [SerializeField] private bool m_IsWalking;
         [SerializeField] private float m_WalkSpeed;
         [SerializeField] private float m_RunSpeed;
         [SerializeField] [Range(0f, 1f)] private float m_RunstepLenghten;
         [SerializeField] private float m_JumpSpeed;
         [SerializeField] private float m_StickToGroundForce;
         [SerializeField] private float m_GravityMultiplier;
         [SerializeField] private MouseLook m_MouseLook;
         [SerializeField] private bool m_UseFovKick;
         [SerializeField] private FOVKick m_FovKick = new FOVKick();
         [SerializeField] private bool m_UseHeadBob;
         [SerializeField] private CurveControlledBob m_HeadBob = new CurveControlledBob();
         [SerializeField] private LerpControlledBob m_JumpBob = new LerpControlledBob();
         [SerializeField] private float m_StepInterval;
         [SerializeField] private AudioClip[] m_FootstepSounds;    // an array of footstep sounds that will be randomly selected from.
         [SerializeField] private AudioClip m_JumpSound;           // the sound played when character leaves the ground.
         [SerializeField] private AudioClip m_LandSound;           // the sound played when character touches back on ground.
 
         private Camera m_Camera;
         private bool m_Jump;
         private float m_YRotation;
         private Vector2 m_Input;
         private Vector3 m_MoveDir = Vector3.zero;
         private CharacterController m_CharacterController;
         private CollisionFlags m_CollisionFlags;
         private bool m_PreviouslyGrounded;
         private Vector3 m_OriginalCameraPosition;
         private float m_StepCycle;
         private float m_NextStep;
         private bool m_Jumping;
         private AudioSource m_AudioSource;
 
         // Use this for initialization
         private void Start()
         {
             m_CharacterController = GetComponent<CharacterController>();
             m_Camera = Camera.main;
             m_OriginalCameraPosition = m_Camera.transform.localPosition;
             m_FovKick.Setup(m_Camera);
             m_HeadBob.Setup(m_Camera, m_StepInterval);
             m_StepCycle = 0f;
             m_NextStep = m_StepCycle/2f;
             m_Jumping = false;
             m_AudioSource = GetComponent<AudioSource>();
             m_MouseLook.Init(transform , m_Camera.transform);
         }
 
 
         // Update is called once per frame
         private void Update()
         {
             RotateView();
             // the jump state needs to read here to make sure it is not missed
             if (!m_Jump)
             {
                 m_Jump = CrossPlatformInputManager.GetButtonDown("Jump");
             }
 
             if (!m_PreviouslyGrounded && m_CharacterController.isGrounded)
             {
                 StartCoroutine(m_JumpBob.DoBobCycle());
                 PlayLandingSound();
                 m_MoveDir.y = 0f;
                 m_Jumping = false;
             }
             if (!m_CharacterController.isGrounded && !m_Jumping && m_PreviouslyGrounded)
             {
                 m_MoveDir.y = 0f;
             }
 
             m_PreviouslyGrounded = m_CharacterController.isGrounded;
         }
 
 
         private void PlayLandingSound()
         {
             m_AudioSource.clip = m_LandSound;
             m_AudioSource.Play();
             m_NextStep = m_StepCycle + .5f;
         }
 
 
         private void FixedUpdate()
         {
             float speed;
             GetInput(out speed);
             // always move along the camera forward as it is the direction that it being aimed at
             Vector3 desiredMove = transform.forward*m_Input.y + transform.right*m_Input.x;
 
             // get a normal for the surface that is being touched to move along it
             RaycastHit hitInfo;
             Physics.SphereCast(transform.position, m_CharacterController.radius, Vector3.down, out hitInfo,
                                m_CharacterController.height/2f);
             desiredMove = Vector3.ProjectOnPlane(desiredMove, hitInfo.normal).normalized;
 
             m_MoveDir.x = desiredMove.x*speed;
             m_MoveDir.z = desiredMove.z*speed;
 
 
             if (m_CharacterController.isGrounded)
             {
                 m_MoveDir.y = -m_StickToGroundForce;
 
                 if (m_Jump)
                 {
                     m_MoveDir.y = m_JumpSpeed;
                     PlayJumpSound();
                     m_Jump = false;
                     m_Jumping = true;
                 }
             }
             else
             {
                 m_MoveDir += Physics.gravity*m_GravityMultiplier*Time.fixedDeltaTime;
             }
             m_CollisionFlags = m_CharacterController.Move(m_MoveDir*Time.fixedDeltaTime);
 
             ProgressStepCycle(speed);
             UpdateCameraPosition(speed);
         }
 
 
         private void PlayJumpSound()
         {
             m_AudioSource.clip = m_JumpSound;
             m_AudioSource.Play();
         }
 
 
         private void ProgressStepCycle(float speed)
         {
             if (m_CharacterController.velocity.sqrMagnitude > 0 && (m_Input.x != 0 || m_Input.y != 0))
             {
                 m_StepCycle += (m_CharacterController.velocity.magnitude + (speed*(m_IsWalking ? 1f : m_RunstepLenghten)))*
                              Time.fixedDeltaTime;
             }
 
             if (!(m_StepCycle > m_NextStep))
             {
                 return;
             }
 
             m_NextStep = m_StepCycle + m_StepInterval;
 
             PlayFootStepAudio();
         }
 
 
         private void PlayFootStepAudio()
         {
             if (!m_CharacterController.isGrounded)
             {
                 return;
             }
             // pick & play a random footstep sound from the array,
             // excluding sound at index 0
             int n = Random.Range(1, m_FootstepSounds.Length);
             m_AudioSource.clip = m_FootstepSounds[n];
             m_AudioSource.PlayOneShot(m_AudioSource.clip);
             // move picked sound to index 0 so it's not picked next time
             m_FootstepSounds[n] = m_FootstepSounds[0];
             m_FootstepSounds[0] = m_AudioSource.clip;
         }
 
 
         private void UpdateCameraPosition(float speed)
         {
             Vector3 newCameraPosition;
             if (!m_UseHeadBob)
             {
                 return;
             }
             if (m_CharacterController.velocity.magnitude > 0 && m_CharacterController.isGrounded)
             {
                 m_Camera.transform.localPosition =
                     m_HeadBob.DoHeadBob(m_CharacterController.velocity.magnitude +
                                       (speed*(m_IsWalking ? 1f : m_RunstepLenghten)));
                 newCameraPosition = m_Camera.transform.localPosition;
                 newCameraPosition.y = m_Camera.transform.localPosition.y - m_JumpBob.Offset();
             }
             else
             {
                 newCameraPosition = m_Camera.transform.localPosition;
                 newCameraPosition.y = m_OriginalCameraPosition.y - m_JumpBob.Offset();
             }
             m_Camera.transform.localPosition = newCameraPosition;
         }
 
 
         private void GetInput(out float speed)
         {
             // Read input
             float horizontal = CrossPlatformInputManager.GetAxis("Horizontal");
             float vertical = CrossPlatformInputManager.GetAxis("Vertical");
 
             bool waswalking = m_IsWalking;
 
 #if !MOBILE_INPUT
             // On standalone builds, walk/run speed is modified by a key press.
             // keep track of whether or not the character is walking or running
             m_IsWalking = !Input.GetKey(KeyCode.LeftShift);
 #endif
             // set the desired speed to be walking or running
             speed = m_IsWalking ? m_WalkSpeed : m_RunSpeed;
             m_Input = new Vector2(horizontal, vertical);
 
             // normalize input if it exceeds 1 in combined length:
             if (m_Input.sqrMagnitude > 1)
             {
                 m_Input.Normalize();
             }
 
             // handle speed change to give an fov kick
             // only if the player is going to a run, is running and the fovkick is to be used
             if (m_IsWalking != waswalking && m_UseFovKick && m_CharacterController.velocity.sqrMagnitude > 0)
             {
                 StopAllCoroutines();
                 StartCoroutine(!m_IsWalking ? m_FovKick.FOVKickUp() : m_FovKick.FOVKickDown());
             }
         }
 
 
         private void RotateView()
         {
             m_MouseLook.LookRotation (transform, m_Camera.transform);
         }
 
 
         private void OnControllerColliderHit(ControllerColliderHit hit)
         {
             Rigidbody body = hit.collider.attachedRigidbody;
             //dont move the rigidbody if the character is on top of it
             if (m_CollisionFlags == CollisionFlags.Below)
             {
                 return;
             }
 
             if (body == null || body.isKinematic)
             {
                 return;
             }
             body.AddForceAtPosition(m_CharacterController.velocity*0.1f, hit.point, ForceMode.Impulse);
         }
     }
 }