To show only one post, use the function get_post.

Example:

post_title;
$sdac_content = $show_post_id->post_content;
?>
<h2></h2>

The code above will show the title and content of the post with the post ID of 10. If you are not sure what your post ID is, go to the manage screen in the WP-Admin, and hover over the post title. In your browser status bar, you will see the URL – and the post ID is the number at the end of the URL.