Handling GameObject by Server and Client (Network Manager)

Hello,
I want to create a Cardboard-App, where you can see around by cardboard and walk with a game controller. I realized that by wireless lan. The player is a Network-Object. The server (my computer) gets the controller-input and send it to the client (smartphone), whereas the client tracks the head-movement (because I dont want to connect my smartphone directly with the controller via usb). Now I want to send the head position to the server, to walk with the controller along the direction of the head. That’s a huge problem for me, because either the client can controll the player object or vice versa, but not both participants can controll it.
I tried to use the deprecated RPC-Calls, too. Thank you for answers!

	void MovementManagement(float horizontal, float vertical, bool sneaking)
	{

		if(!isServer)
		{
	
			if (isLocalPlayer) {
				transform.Rotate(new Vector3(0,Input.GetAxis("Mouse X")*3,0));
			}

			return;
		}

		anim.SetBool (hash.sneakingBool, sneaking);
		if (horizontal != 0f || vertical != 0f) {

			anim.SetFloat (hash.speedFloat, 5.5f, speedDampingTime, Time.deltaTime);

			transform.position += (transform.forward * vertical + transform.right * horizontal ) * speed;

		} else {
			anim.SetFloat (hash.speedFloat, 0f);
		}


	}

Input.GetAxis(“Mouse X”) stands for the head-position. It’s just for test, sry I forget to mention that.