Why can't I go to the checkout page?

Question

WordPress

Why does a blank page open with header and footer. What am I doing wrong ? The page itself contains the required shortcode, the page is assigned correctly. In the woocommerce.php file, I now have the code

<?php get_header(); ?>
    <main id="main" class="defaolt_main">
        <section class="row">
            <?php woocommerce_content(); ?>
        </section>
        <?php get_sidebar(); ?> 
    </main> 

<?php get_footer(); ?>

Are there links to a resource that shows the correct connection?