need help sos plz

i need to call a specific post but i get error and
mistakes when i try to do it alone 🙁 still learning
how to in wordpress..

this is the code:

<div class="postdata">
<?php $postmeta = get_post_meta($post->ID, 'feature-image', true); if($postmeta != ""){ ?>
 <div class="postimg"> <?php echo $postmeta; ?> </div>
<?php } ?>
<div class="post">
 <div class="p-head">
  <h1><a href="<?php the_permalink(); ?>"><?php the_title()?></a></h1>
   <p class="p-date-cat"><?php the_time('F j, Y') ?> | בקטגוריה: <?php the_category(', ') ?></p>
 </div>
<div class="p-con"><p><?php echo truncate($post->post_content,630); ?></p></div>
 <ul class="p-det">
  <li class="p-det-com"><?php comments_popup_link('פרסום תגובה', 'תגובה אחת', '(%) תגובות'); ?></li>
  <li class="p-det-more"><a href="http://israel-blog.co.il/wp-signup.php">פתיחת בלוג בחינם...</a></li>
 </ul>
</div>

How can i change it to get a specific post ?

hope you can help, kinda lost