For importing demo content for your site you must go to ‘Tools’->’Import’:
Press ‘Run Importer’:
In package that you have downloaded from Themeforest there is folder Demo-data with 2 files. One file is a XML file and other file is a WIE file:
Now you must select XML file: ‘silvera.wordpress.2016-07-05.xml’:
Choose ‘Download and import file attachments’ and press ‘Submit’.
Now you can see demo content on your site: