How to create Astra theme custom Attachment page

<?php
/**
 * attachment.php
 * The template for displaying all attachment single posts.
 * Custom Attachment page by Fahim Murshed
 * https://fahimm.com
 *
 * @link https://developer.wordpress.org/themes/basics/template-hierarchy/#single-post
 *
 * @package Astra
 * @since 1.0.0
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit; // Exit if accessed directly.
}

get_header(); ?>

<?php if ( astra_page_layout() == 'left-sidebar' ) : ?>

    <?php get_sidebar(); ?>

<?php endif ?>

    <div id="primary" <?php astra_primary_class(); ?>>

        <?php astra_primary_content_top(); ?>

        <h1 class="post-title"><?php the_title(); ?></h1>

        <?php
        echo wp_get_attachment_image( get_the_ID(), 'large' );

        echo "<hr><p class='resolutions'> Downloads: ";

        $images = array();
        $image_sizes = get_intermediate_image_sizes();
        array_unshift( $image_sizes, 'full' );
        foreach( $image_sizes as $image_size ) {
            $image = wp_get_attachment_image_src( get_the_ID(), $image_size );
            $name = $image_size . ' (' . $image[1] . 'x' . $image[2] . ')';
            $images[] = '<a href="' . $image[0] . '">' . $name . '</a>';
        }

        echo implode( ' | ', $images );
        echo "</p>";

        astra_content_loop();
        ?>



        <?php

        ?>
        </p>


        <?php astra_primary_content_bottom(); ?>

    </div><!-- #primary -->

<?php if ( astra_page_layout() == 'right-sidebar' ) : ?>

    <?php get_sidebar(); ?>

<?php endif ?>

<?php get_footer(); ?>