This is an update with full illustrations to an older post.
Basic Method:
1) Find your sidebar.php file.
2) Make a copy of it.
Name it sidebar-secondary.php. Your second, third, forth, etc. sidebars
all need to start with sidebar-NAMEHERE.php. That’s part of the naming
convention in WordPress.

3) Make the content changes you need in secondary sidebar file.
This is where you make the secondary sidebar different. Whatever it is
you need to be different should go in this file. Save
sidebar-inside.php and upload it to your server.
4) Locate your single.php file.
5) Look for a line near the end of the file that looks like this: <?php get_sidebar(); ?>
6) Change it to <?php get_sidebar(‘inside’); ?> (note, the ‘inside’ part should match the name of the new sidebar-inside.php file). The single quote marks ‘ ‘ are required. [Read more...]
