[Solved] Custom page template

Your code will only display a list of your posts if the page that is using that template is set to be the Posts Page (in admin settings).

If you want any other page to display a list of posts, then you need to write a custom query inside the template.

E.g. using WP_Query:

$args = array(
    'post_type'      => 'post',
    'posts_per_page' => -1
);

$query = new WP_Query($args);

<div class="content">

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

    <div class="container">
        <div class="row">
            <?php while ( $query->have_posts() ) : $query->the_post();?>
                <?php get_template_part( 'template-parts/blog-2-col', get_post_format() );?>
            <?php endwhile; ?>
        </div><!-- row -->
    </div><!-- ontainer -->

    <div class="container">
        <div class="row">
            <div class="col-sm-12">
                <?php wpbeginner_numeric_posts_nav(); ?>
            </div>
        </div>
    </div>

<?php else :?>
    <?php get_template_part( 'template-parts/content', 'none' );?>
<?php endif; ?>

Or, you could create a shortcode which would contain pretty much the same code as above. And then you could use that shortcode in the page’s content. Then, in the template:

if(have_posts()){
    while(have_posts()){
      the_post();
      the_content();
   }
}