To import the demo content, grab the export from here and follow the instructions provided by Wordpress:
To import from a WordPress export file into a WordPress blog follow these steps.
1. Log into that blog as an administrator.
2. Go to Tools-> Import in the blog’s admin panels.
3. Choose “WordPress” from the list.
4. Upload this file using the form provided on that page.
5. You will first be asked to map the authors in this export file to users on the blog. For each author, you may choose to map to an existing user on the blog or to create a new user
6. WordPress will then import each of the posts, comments, and categories contained in this file into your blog
Once the xml file has been imported into your theme you will still need to browse through your Wordpress backed to ‘Settings’ -> ‘Reading’ and set your ‘profile’ page to home, and your ‘blog’ page to your blog page.