Object won't move with mouse

I’m starting to try out Unity for the first time today and have been doing a few tutorials. I’ve followed all of the steps correctly, but now I’m stuck. I basically want to move an object on the x-axis and have it follow the cursor. Currently, it doesn’t do anything. Any help to get me back on the right track would be appreciated. This is the code I have:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class HatController : MonoBehaviour

    public Camera cam;

    // Start is called before the first frame update
    void Start()
        if (cam == null)
            cam = Camera.main;

    // Update is called once per physics timestep
    void FixedUpdate()
        Vector3 rawPosition = cam.ScreenToWorldPoint(Input.mousePosition);
        Vector3 targetPosition = new Vector3(rawPosition.x, 0.0f, 0.0f);

In the update function you can try this…

void update()
float mouseposition = Input.mousePosition.x / Screen.width * screenWidthInUnits;  // this is the unity units from left side of screen to right so make sure you get that right.
vector2  ObjectWantToMove = new Vector2(mouseposition , transform.position.y); // change x axis and keep the y axis same for the object 

transform.position = ObjectWantToMove;

// This is what i did for my Arkanoid game to move paddle along with mouse. Hope it helps