If you do Importing Demo Data after running WooCommerce Setup Wizard, you may find there duplicate store pages (shop, cart, checkout, etc.) as the setup wizard will create these pages automatically if they do not exist. These store pages also block the importing process from registering the demo’s store pages, you can fix it by either changing navigation menu item to use store pages created by WooCommerce or declare demo’s store pages in WooCommerce settings .
To run WooCommerce Setup Wizard
WooCommerce Setup Wizard takes you through all necessary steps to set up your store and get it ready to start selling. If you haven’t run it yet, you will see a notification in your WordPress Admin as following:
Click the Run the Setup Wizard button, this will take you to the first page of the setup wizard, you can then follow the wizard to tweak necessary settings for your store.