Scriptum/Assets/SaveMusicSettings.cs

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

public class SaveMusicSettings : MonoBehaviour
{
    [SerializeField] private Slider musicSlider = null;

    private void Start()
    {
        LoadValues();

        if (!PlayerPrefs.HasKey("musicVolume"))
        {
            PlayerPrefs.SetFloat("musicVolume",0.1f);
            Load();
        }
        else
        {
            Load();
        }
    }

    public void ChangeVolume()
    {
        AudioListener.volume = musicSlider.value;
    }

    private void Load()
    {
        musicSlider.value = PlayerPrefs.GetFloat("musicVolume");
    }

    private void Save()
    {
        PlayerPrefs.SetFloat("musicVolume", musicSlider.value);
    }
    
    public void SaveVolumeButton()
    {
        float musicValue = musicSlider.value;
        PlayerPrefs.SetFloat("MusicValue", musicValue);
        LoadValues();
    }

    void LoadValues()
    {
        float musicValue = PlayerPrefs.GetFloat("MusicValue");
        musicSlider.value = musicValue;
    }
}