Import test data to theme? I'm quite new to Drupal, and I'm still in learning process. I've installed a pure Drupal 8, and installed a the YG Agency theme. Right now the theme is only blank. Is it possible to load some test data into the theme, as it is displayed in the Demo?

http://demo.drupalfreethemes.com/drupal/free-themes/yg_agency/

I know this can be done is many WordPress themes? Does Drupal support importing test data to themes as well?
The YG Agency theme has a link to the prepopulated database from the following page:

https://www.drupal.org/project/yg_agency

Just click on the link that says "Download Demo Site".

You can then import the database into MySQL or the like.