To access settings for the side navigation, go to:

Structure > Block layout > Block types

 

drupal block types

Then select Illinois Framework Theme

 

Illinois Framework Theme block layout option screenshot
  1. Scroll down to the heading Sidebar First, and select "Configure" to the far right of Main navigation as shown below.

     

    drupal sidebar first settings screenshot

    2. < 

  2. Under Configure block, scroll down to "Number of levels to display" select "Unlimited"

     

    block configuration settings screenshot

    3. < 

  3. Under Advanced options, scroll down to "Use as title" select "Active trail's root title"

     

    drupal sidebar use as title screenshot