Unity How to use the variables loaded from json string as input in the update section

I am quite new to Unity and C# coding in general so my question might be silly to some of you but I am currently trying to create a button at the location in which its coordinates are from a json string. I am just don't where to go next from here to archive my goals. How can I use the xcoor from json as input in update? Here is my code:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Networking;
using UnityEngine.UI;
using SimpleJSON;

public class JSONcontroller : MonoBehaviour
{
    public GameObject obj;
    Vector3 buttonPos;
    private string url = "http://localhost:3000/coordinates/";

    // Start is called before the first frame update
    void Start()
    {
        StartCoroutine(getData());
        
    }

    IEnumerator getData()
    {
        UnityWebRequest request = UnityWebRequest.Get(url);
        yield return request.SendWebRequest();
        if(request.isNetworkError||request.isHttpError)
        {
            Debug.LogError(request.error);
            yield break;
        }
        JSONNode coordinates = JSON.Parse(request.downloadHandler.text);
        string xcoor = coordinates["x1"];
        string ycoor = coordinates["y1"];
        //Debug.Log(xcoor);


    }

    // Update is called once per frame
    void Update()
    {
        buttonPos = new Vector3(xcoor, ycoor, 4f);
        if (Input.GetButton("Fire1"))
            Instantiate(obj, buttonPos, Quaternion.identity);
    }
}

and my sample json file

{
  "coordinates": [
    {
      "id": 1,
      "x1": "5",
      "y1": "2"
    },
    {
      "id": 2,
      "x1": "3",
      "y1": "5"
    },
    {
      "id": 3,
      "x1": "5",
      "y1": "7"
    }
  ]
}