Sample Data isn’t automatically added to your site, for most people this wouldn’t be beneficial, instead there are specific files included to import sample data.
When you go to download your purchase click on Download->Main files. After this folder downloads, unzip it and locate the folder called “SampleData”.
Within this folder you will find your sample data file(s).
Before uploading your Sample data you might want to install and activate the recommended plugins (please refer to the documentation) to help prevent any errors after import.
To upload your WordPress sample data, log into your WP install and browse to Tools->Import and follow the instructions.
After the import is complete you should have all the posts/pages from the demo with dummy images.
There are certain things a WP import can not do, so after uploading sample data
Go to Appearance->Menu to set your menu locations.
Go to Appearance->Widgets to add your widgets (widgets aren’t included in a WordPress export)
Set your homepage at Settings->Reading using the “Home” page as a static page.
Go to Appearance->Theme Options to setup your theme options.