The new pages don`t show in the project download folder.

Adding custom post types manually or using a plugin only adds the functionality of adding and editing custom posts in the backend (WordPress Dashboard). The data is stored in your database. To output this data on the frontend, you need custom template files. Compare the code in the tutorial with your code and check for any differences.

Also, I was wondering if these Custom Post Type pages could be used for galleries as well, with let's say 20 photos per page?

Jup, you can loop through custom post types just like default posts. You'll need to create a custom page template and add a custom loop to achieve this. Example Code for looping through 20 custom posts in a custom page template below. Just change the name of the custom post type to the name you defined. In my example code bellow i created a variable called $custom_post_type and gave it the string value of 'example'. Replace 'example' with the name of your custom post type.

Inside of the while loop add the code that displays the data of your custom post type you want to output in the frontend. e.g. the_title(); the_content(); the_post_thumbnail(); etc.

If you are using custom fields with the "Advanced Custom Fields" plugin you can add field functions here too. e.g. the_field('fieldname');

 <?php get_header();

/* Template Name: Your Template Name */

 ?>


 <?php 

    $custom_post_type = 'example';
    $post_amount = 20;

    $args = array( 'post_type' => $custom_post_type, 'posts_per_page' => $post_amount);

    $loop = new WP_Query($args);

     if ($loop->have_posts()):

            while ($loop->have_posts()) : $loop->the_post(); ?>

                <!-- Post content functions comes here  e.g. the_title(); -->

            <?php endwhile;

        endif;

        wp_reset_query();?>


 <?php get_footer();?>

Now to get this all working together you have to create a new page in the WordPress dashboard. Then edit the page and there should be a menu dropdown in the sidebar for choosing a template. Choose the template name you defined in your code. (in the example above this would be: "Your Template Name")