PlaySound Once After Activated

So I have a door that Activates once the Player Enters Its Collider.
I only need the sound to play once but I am terrible with Scripting.
After the door is already opened the Player can collide with it and it will play the sound again,
as i intend it to only play once.
Ive Tried Changing _audioSource.Play(); to _audioSource.PlayOneShot(); but it doesnt seem to work. I have also
watched numerous tutorials and looked at other peoples questions but they all seem to be
extremely specific and dont match with my problem.

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

public class DoorScript : MonoBehaviour

private Animator _animator;
private AudioSource _audioSource;

private void Awake()
    _animator = GetComponent<Animator>();
    _audioSource = GetComponent<AudioSource>();

private void OnTriggerEnter(Collider other)
    if (other.CompareTag("Player"))
        _animator.SetBool("open", true);



So two things:

First, make sure that the audiosource isn’t called on multiple times. This could happen for multiple reasons due to multiple colliders on the player, or the sound being called in other scripts.

Otherwise, the audiosource could be on ‘loop’. If ‘loop’ is off the sound should only play once.

Second, is a question. Is the door animated? If so, there may be a easier way of timing your sound and having it only play once.