Make a Jump Delay

How i can make a jump delay in this script?

         private void Update()
         {
             if (!m_MouseLook.mIsPaused)
                 Crouching = inputManager.GetButtonDown("Crouch");
             anim.SetBool("crouch", Crouch);
 
             RotateView();
             // the jump state needs to read here to make sure it is not missed
             if (!m_Jump && !m_onLadder)
             {
                 if(!m_MouseLook.mIsPaused)
                 m_Jump = inputManager.GetButtonDown("Jump");
             }
 
             if (!m_PreviouslyGrounded && m_CharacterController.isGrounded && !m_onLadder)
             {
                 m_MoveDir.y = 0f;
                 m_Jumping = false;
             }
             if (!m_CharacterController.isGrounded && !m_Jumping && m_PreviouslyGrounded)
             {
                 m_MoveDir.y = 0f;
             }
 
             if (isSwimming && inputManager.GetButton("Jump"))
                 m_MoveDir.y = 2.5f;    
 
             m_PreviouslyGrounded = m_CharacterController.isGrounded;
 
             if (m_onLadder)
             {
                 StopAllCoroutines();
                 rigidbody.useGravity = false;
                 rigidbody.isKinematic = true;
                 LadderUpdate();
             }
             else
             {
                 LadderObject = null;
                 rigidbody.useGravity = true;
                 rigidbody.isKinematic = true;
             }
         }
 
         private void FixedUpdate()
         {
             float speed;
 
             GetInput(out speed);
             
             if (!m_onLadder)
             {
                 // 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)
                 {
                     if (Crouching)
                         OnCrouch();
 
                     m_MoveDir.y = -Stats.m_StickToGroundForce;
 
                     if (m_Jump)
                     {
                         rigidbody.velocity = new Vector3(0,0,0);
 
                         if (Crouch)
                             OnCrouch();
 
                         else
                         {
                             m_MoveDir.y = Stats.m_JumpSpeed;
                             m_Jump = false;
                             m_Jumping = true;
                         }
                     }
                 }
                 else
                 {
                     if (Crouch)
                         OnCrouch();
 
                     m_MoveDir += Physics.gravity * Stats.m_GravityMultiplier * Time.fixedDeltaTime;
                 }
                 m_CollisionFlags = m_CharacterController.Move(m_MoveDir * Time.fixedDeltaTime);
             }
 
             if (Crouch &&!isSwimming)
             {
                 Stats = CrouchStats;
             }
             else
             {
                 Stats = saveStats;
             }
         }