How to create a custom template for this custom post type?

Create a File named archive-{yourposttype}.php and Then start tweaking from there. You can style this archive file to your heart’s desire. A very basic template would look like this:

<?php
get_header();
if(have_posts()) : while(have_posts()) : the_post();
    the_title();
    echo '<div class="entry-content">';
    the_content();
    echo '</div>';
endwhile; endif;
get_footer();
?>