Add a delay before sound is played

I’ve got a bit of Javascript to play an audion on clicking an element:

    const btn1 = document.querySelectorAll(".btn-sound-1");
    let audio1 = new Audio('https://nullsieben.co.uk/74.mp3');

    btn1.forEach(btn => {
        btn.addEventListener("click", () => {
            audio1.play();
        });
    });
   

https://jsfiddle.net/wjq0ydhz/

I’d like to add the following:

1. Delay from clicking the button until the mp3 starts paying
2. Is there a way with this code to pre-load the sound so that it definately will when it’s supposed to, regardless of bandwidth etc.?