If you wish to the demo content via WordPress importer plugin and using wp native import command. For this you need to have the WordPress importer plugin installed on your website
Step 1 : Log into your WordPress Dashboard and navigate to Tools > Import. Then click on WordPress
Step 2 : Install and Activate importer plugin. Then select the XML file from your theme download file “content.xml” , it will be in a folder called “Demo Content”.
Step 3 : Once uploaded it will ask you to import the data into your WordPress user account select from the drop-down an existing user, also click on the check box that says “Download and import file attachments” Once complete all the data will be imported into your site. Do not interrupt/cancel the import process!