Keep in mind that this article refers to the "Apprentice" theme feature. We do have a stand-alone plugin as well, called "Thrive Apprentice".
When you activate the Apprentice feature, one of the new theme options lets you select a "Lessons Root Page":
The page you select here will act as an alternative homepage for Apprentice pages.
The Lessons Root Page is linked to in two different ways: when someone clicks on the first item in the breadcrumbs of an Apprentice Lesson or when someone clicks on the site logo on an Apprentice Page or in an Apprentice Lesson.
If you have your site set up with a public-facing part and a member's area, this is a great feature.
Someone looking at a lesson will not expect to be sent to your homepage when clicking on the root link in the breadcrumbs. Sending them to your member welcome page makes much more sense.