If you can not install the sample data using the One-Click import or you want to do so manually, follow the steps below.
Go to Appearance > Install Demos, click the demo you want to import and install all the required plugins.
Download the demo data zip file and store it on your computer. Unzip the zip file – DEMO DATA
Find the content.xml file from demo data zip file, log into your WordPress website and navigate to Tools > Import to begin the import process. Click on the WordPress option, Upload file and import.
First, install and activate the free plugin Customizer Export/Import, then go to Customizer > Export/Import and import the customizer.dat file.
First, install and activate the free plugin Widget Importer & Exporter, then click Tools > Widget Importer & Exporter and import the widgets.wie file.