This step is optional if you want to build your website from scratch. As it was noted before, you can install "One Click Demo Import" plugin from recommended plugins list. Then you will be able to import demo content. Find "Import Demo Data" item in the "Appearance" menu. All that you need is a single click "Import" button and demo content will be imported. It may take up to 5 minutes, so don't close active tab in your browser until content gets imported.
All demos was created using classic WordPress editor (and "Layout helper" grid builder), so if you are using WordPress 5.0 +, you should activate it as well.
Please add the following code to your .htaccess if importing fails for some reason (or ask your hosting support to do this for you):