The featured posts area on the front-page requires Jetpack to be installed and activated in order to work. If it is, you can follow these steps to use the feature:
- From your Dashboard, navigate to Appearance > Customize.
- Find the "Featured Content" header in the menu on the left, and click to expand it.
- Enter a tag that you would like to use to specify which posts are shown in the Featured Content area.
- Save your changes.
That's it! Now, posts that have the tag that you specified will show in the Featured Content area on the front-page.