How do I make a responsive grid consisting of square images?

On my website, I would like to add a grid consisting of square images (album covers). I also want to add this hover effect to said images: https://codepen.io/jarvis-ai/pen/GRJpQWO. How would I do this?

I have already tried a couple of things I found while researching my question but I never got the result I wanted. I have always had issues with the sizing of the images and making the sizes responsive. Here is a visualization of what I want it to look like and what I to happen:

1. Grid on a normal-sized monitor:

2. Grid on a smaller monitor or window:

1. Image on hover:

Pretty much: If the page is viewed on a normal-sized monitor, there should be 4 images in one row. If the page is viewed on a phone or if the window is resized, the images split into more rows with one row containing less than 4 now. If the mouse is being hovered over an image, the image should do the effect thing.

Notice: I should be able to do the hover effect by myself since there is already a working demo. I am just mentioning that I want the effect so that you can give me a solution that works with the effect.

Here is the last thing I have tried:

#music {
  width: 100%;
  min-height: 100vh;
  background-color: var(--grey);
  display: flex;
  color: var(--white);
  justify-content: center;
  align-items: center;
  text-align: center;
  flex-direction: column;
}

#cover-section {
  display: flex;
  align-items: center;
  vertical-align: middle;
  justify-content: center;
  flex-direction: row;
}

.cover {
  flex: 1 0 21%;
  width: 100%;
  height: auto;
  background-image: url(https://commons.wikimedia.org/wiki/File:Stack_Overflow_icon.svg);
}

<div id="music">
  <div id="cover-section">
    <div class="cover"></div>
    <div class="cover"></div>
    <div class="cover"></div>
    <div class="cover"></div>
    <div class="cover"></div>
    <div class="cover"></div>
    <div class="cover"></div>
    <div class="cover"></div>
    <div class="cover"></div>
  </div>

Thanks in advance for your help!

By the way: If I need JavaScript to achieve this, please do not tell me to just use JavaScript but give me some code I could use, as I have done next to nothing with JavaScript before.

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