how to show a category from a CPT?

Question

WP_Query is the solution to your problem.

Go through the available parameters. Just add a query and a loop in your page template and you are good to go.

Ex.

$args = array(
'category_name' => 'winter',
'orderby' => 'rand',
'posts_per_page' => 10
);

$query = new WP_Query( $args );

The loop starts here:

<?php if ( $query->have_posts() ) : while ( $query->have_posts() ) : $query->the_post(); ?>

and ends here:

<?php endwhile; else: ?>
<p><?php _e('Sorry, no posts matched your criteria.'); ?></p>
<?php endif; ?>