I need help with my Timer to reset and start it with the click of a button

I have something wrong with my Parkour game with the timer. and I want it to stop when I press the R key, this is the code and I hope that someone can help me.

Cannot implicitly convert type ‘string’ to ‘float’

thanks

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using TMPro;
using UnityEngine.UI;

public class Timer : MonoBehaviour
{
    [Header("Component")]
    public TextMeshProUGUI TimerText;
    private float stopTime;


    [Header("Timer Settings")]
    public float currentTime;
    public bool countDown;
    private bool isRunning = false;


    // Start is called before the first frame update
    void Start()
    {
        isRunning = true;
    }

    // Update is called once per frame
    void Update()
    {
        currentTime = countDown ? currentTime -= Time.deltaTime : currentTime += Time.deltaTime;
        TimerText.text = currentTime.ToString();
    }

    public void TimerReset()
    {
        if (Input.GetKeyDown(KeyCode.R));
        {
            print("RESET");
            stopTime = 0;
            currentTime = "00";
            isRunning = false;
        }
    }
}

Hello @Robbie_VR, the error means what it says.
In your script you create a float variable.

But later you set it to a string value.

This cannot be done without converting the string to a float, but I think you can just axe the quotation marks and call it a day.