For importing Demo contents using the One Click Demo Import plugin, firstly you should download the demo content file.

1. After installing and activating the One Click Demo Import plugin, navigate to the Dashboard > Appearance  > Import Demo Data.
2. Select respective files for Import Content, Import Widgets, and Import Customizer.
3. Click on the Continue & Import button.

The demo data will be imported in a couple of minutes.

Note: Please do not refresh the page until the import is completed.