When creating a new page its address normally looks like “domain.com/page_name”.
How to create a page using WP or GP tools, that would have address “domain.com/whatever/page_name”?
Create page, call it whatever, for example “free”,
Create pages you want, call them whatever, for example “lesson1”, “lesson2”, “lesson3”,
Go to Pages, open page you want to apply child-parent settings,
in Page Attributes section set child-parent dependencies
associate pages “lesson1”, “lesson2”,.. with page “free”,
save.