Trouble displaying sidebar advertisement on every page

the sidebar behavour is so by design in Twenty Eleven.

please don’t edit the default theme Twenty Eleven directly – it is important to have an unedited default theme in case of serious problems.
please create a child theme to make the edits there: https://codex.www.ads-software.com/Child_Themes

when your child theme is in place, there is a solution available to have sidebars in single posts.

Ok, we’re getting somewhere. Thanks very much for you help.

I’ve created a Child Theme file in it’s own folder within my website, and filled in all the details as per the instruction page, however I’m not certain how to make the sidebar advertisement show up.

If it helps, the sidebar advert (jpg file) is located here.

According to another WordPress help page, I think the code is
<?php include (‘sidebar2.php’); ?>
However I’m not certain if this is correct, and more importantly, even if it is the right code to use, I have no idea where to insert this line into the child page.

Is anyone able to tell me where to put this line (if it’s correct)?

activate the child theme;

if you want the same sidebar to show in single posts as on the front page, edit single.php (copy single.php from Twenty Eleven into the child theme folder) and add the <?php get_sidebar(); ?> code before the ‘get_footer’ line.

then edit functions.php of the child theme (if it does not yet exist, create an empty functions.php file in the child theme) and add this code:
(if you have a new, empty functions.php, you need to add <?php first to the start – make sure there is no other character before that)

add_filter('body_class', 'adjust_singular_body_class', 20, 2);
function adjust_singular_body_class($wp_classes) {
if( is_single() ) :
// Filter the body classes
      foreach($wp_classes as $key => $value) {
      if ($value == 'singular') unset($wp_classes[$key]);
      }
endif;
return $wp_classes;
}

Ok, will try that now. Thank you very much.

Mr Alchymyth, I love you, and I think I want your babies.

(It works, thank you very very very much)

Three nights of toil have been solved in 2 minutes thanks to your help. There’s a bucketload of good karma heading your way I’m certain. ??

Cheers!
Gavin