Blossom - Social Sharing Icons Setup

This theme uses the Jetpack plugin, which can be obtained  here or by searching in 
Dashboard > Plugins > Add New

Once installed and activated, sync this with your WordPress.com account. If you do not have an account there, you will need to create a free account. 

Navigate to  Jetpack > Settings > Engagement and click on the arrow to the right of Sharing to begin editing the settings. Verify that the settings match the screenshot below.