Begin by dragging and dropping your sound file into the assets folder.

For example, in this scenario, we've dragged a sound file that plays when the player wins.

After that, drag the audio clip from the assets folder into the effects list within the sounds manager.

Now, add the following line to the winning condition.

private void OnTriggerEnter2D(Collider2D collision)
{
    if (collision.tag == "win")
    {
        winPanel.SetActive(true);
        SoundManager.instance.PlayEffect(1);
    }
}

In this Unity script, the OnTriggerEnter2D method is used to detect when a game object with a 2D collider enters a trigger zone. If the object has a tag labeled "win", the script activates a UI element called winPanel to display a winning message or screen.

Simultaneously, it calls the PlayEffect method from the SoundManager singleton instance to play a sound effect. The sound effect played is the one located at index 1 in the sound manager's effects list, which is typically pre-configured in the Unity editor.

You can add more sound effects with this way, and everything will work perfectly.