How do I make a PHP file work inside an HTML with Bluehost

one text

So I am trying to make a PHP file look through my database, find all of my images, and print them, I have watched a few people do this to make sure I got the code right since I am a little new to PHP. the code is

<?php
$dir_path    = 'Albums/portaits';
$ext_array = array('jpg', 'png', 'jpeg');

if(is_dir($dir_path))
{
    $files = scandir($dir_path);
    
    for($i = 0; $i < count($files); $i++)
    {
        if($files[$i] !='.' && $files[$i] !='..')
        {
            //get file name
            echo "File Name -> $files[$i]<br>";
            
            //get file ext
            $file = pathinfo($files[$i]);
            $extension = $file['extension'];
            echo "File Extension-> $extension<br>";
            echo "img src='$dir_path$files[$i]'>";
        }
    }
} ?>`

I have no idea how to input or call this in HTML and I am unable to do the same as the people in the video.

I am sure that the images are on the server doing mysite.come/images. I see the directories and all on the site. My plan is to make a portfolio page, where I have a little drop-down (that's all css and I think I understand that much lol) and it displays the images of what the PHP calls. the idea is that I won't need to add 50 lines of <img> and I can add images by just uploading an updated folder