"A Page of Posts" tutorial: Can't get it to work, please help

I dont have an issue with this code.

create a custom page like below

<?php
/* Template Name: Category Page */
get_header(); ?>

<?php

if (is_page() ) {
$category = get_post_meta($posts[0]->ID, 'category', true);
}
if ($category) {
  $cat = get_cat_ID($category);
  $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
  $post_per_page = 4; // -1 shows all posts
  $do_not_show_stickies = 1; // 0 to show stickies
  $args=array(
    'category__in' => array($cat),
    'orderby' => 'date',
    'order' => 'DESC',
    'paged' => $paged,
    'posts_per_page' => $post_per_page,
    'caller_get_posts' => $do_not_show_stickies
  );
  $temp = $wp_query;  // assign orginal query to temp variable for later use
  $wp_query = null;
  $wp_query = new WP_Query($args);
  if( have_posts() ) :
		while ($wp_query->have_posts()) : $wp_query->the_post(); ?>
	    <div <?php post_class() ?> id="post-<?php the_ID(); ?>">
        <h2><a>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h2>
        <small><?php the_time('F jS, Y') ?> <!-- by <?php the_author() ?> --></small>
        <div class="entry">
          <?php the_content('Read the rest of this entry ?'); ?>
        </div>
        <p class="postmetadata"><?php the_tags('Tags: ', ', ', ''); ?> Posted in <?php the_category(', ') ?> | <?php edit_post_link('Edit', '', ' | '); ?>  <?php comments_popup_link('No Comments ?', '1 Comment ?', '% Comments ?'); ?></p>
      </div>
    <?php endwhile; ?>
    <div class="navigation">
      <div class="alignleft"><?php next_posts_link('? Older Entries') ?></div>
      <div class="alignright"><?php previous_posts_link('Newer Entries ?') ?></div>
    </div>
  <?php else : ?>

		<h2 class="center">Not Found</h2>
		<p class="center">Sorry, but you are looking for something that isn't here.</p>
		<?php get_search_form(); ?>

	<?php endif; 

	$wp_query = $temp;  //reset back to original query

}  // if ($category)
?>

<?php get_sidebar(); ?>
<?php get_footer(); ?>

Then in the backend off wordpress add new page make sure its using the custom template off Categroy Page.

Make sure you have a catgeory called news or something.

Then add a custom field with a name of category

and a value off news or whatever you have called your category.

Then I created a new post where I added the tag “new-page” to it.

tag or category?

Hi isimpledesign, I’ll try your solution later.

And alchymyth, I add a tag to my new post. They are already categorised.

your code is looking for the specific category ‘new-page’ not a tag ‘new-page’

'category__in' => array($cat),

if you want posts with a tag, you have to rewrite the code

Hmm, it does make sense thats the problem – you do not happen to know how the code should be for tags instead of categories?

Otherwise I suppose I can make it work with the categories instead of tags.

here is a go: https://wordpress.pastebin.com/cKJtJseh

warning: untested

make backup copies of your working theme files before editing anything