How do I enable Lessons subpage navigation in the Tool Menu?

Go to Site Info.

Select the Site Info tool from the Tool Menu of your site.

Click Manage Tools.

Check the box to Enable Lessons subpage navigation in the left tool menu.

Scroll down and click Continue.

The subpages will display.

Note: Only one level of subpage will be added to the menu, regardless of how many additional pages are nested within those subpages.