Please read the document on the concrete5 site for package installation. https://documentation.concrete5.org/editors/dashboard/add-functionality
No. Do not remove any content or files from this website.
Yes. Reset site content with the content found in this package
Be careful, because you'll erase the content of your site already there.
It may take some time to install.
The background image of the design customization presets is not displayed only first when install sample content.
The concrete5 has some issues when installing sample content.
Please set it in reference to Instruction, Theme Options and Live Demo.