After importing the demo data you gotta select the LearnPress Pages from the LearnPress settings.
Note: LearnPress plugin create few pages when it’s installed. If you import this theme demo you will have those pages as well.
Now it’s time to select those pages from the LearnPress settings.
Navigate to the LearnPress > Settings > Pages. Here you will see like the screenshot bellow. Select the Profile page, from the profile dropdown.
Select the Become a teacher page same way, like the screenshot bellow.
Select the checkout page, same way from the checkout tab.