background-slideshow is a function based on the jQuery
Simply import the script in your html and call the slider() function.
<div class="bg"></div>
<script>
slider(".bg", 3000, [
'https://cdn.mkava.pl/img/background-slideshow/1.jpg',
'https://cdn.mkava.pl/img/background-slideshow/2.jpeg',
'https://cdn.mkava.pl/img/background-slideshow/2.jpeg'
]);
</script>MIT © Marek Kava