The option is not available to use static image in place of homepage slider.
You need to set image slider to display images on main page.
To display slider:
1. Create 3 pages for slider from Pages -> Add New
2. Add title, description and set Featured Image (This featured image will be your slider image)
3. Go to the Appearance -> Theme Options Panel -> Slider Section -> Select slider pages
Please check the documentation
The demo content file works only with Wide Range PRO version.
The XML file of demo data is not available for free theme.