Installing the demo content in Crexis theme is truly easy. Just navigate to the Theme Options panel and click on the "Demo Import" tab:
You will see a list of all available theme demos. It's very important to import the Base Demo Content first. It contains all example portfolio, testimonials posts and photos that are required by all other demos. That's why it's the longest one to get imported: usually it takes ~90 seconds and depends on your server connection speed. After you import the Base Demo Content you can go ahead and import any other demo content.
If you encounter any issues regarding the demo import process, please check this article.