Deleting a lessons page is a two-part process. First, you must remove the Lessons page from the Tool Menu or page link, and then you can delete it from the site.
Go to Lessons.
Click on the Lessons tool to display the page you want to delete.
Click More Tools, then Remove Page.
From the More Tools drop-down menu, select Remove Page.
Next, go to the Index of Pages.
Select page/s, then click Delete selected pages.
You will see the list of pages with the unused pages listed at the bottom. Only items that are not linked from any other location can be permanently removed from the site.
Click Delete selected pages to completely delete the selected page/s from the site.