» Could I install the theme with sample data like in Joomla?
C5 Extras > Support > Knowledge Base > General > General Themes > Could I install the theme with sample data like in Joomla?

The content depends on what you have currently in your default installation. If you have installed C5 with content in it then you should be able to see some of the blocks displayed. The content is further explained here. However, not all blocks will be present by default upon theme installation so won't be able to see the exact replica of the demo. Nevertheless, what you see in the demo theme should be possible with your installation.