You can get those social-media icons to appear automatically in the sidebar by following these steps:
- Make sure the Jetpack plugin is active and connected to your WordPress.com account (I see you're already running it, so you've already got this part taken care of!)
- In the Jetpack settings area, activate the Publicize module
- Under Settings > Sharing, connect to your preferred social network(s)
- Under Appearance > Customize, in the Connect panel, select the appropriate social-media accounts and save your settings.
- The social-media icons for the accounts you've selected should now appear in your sidebar, and your posts will automatically be shared with those networks on publication. If you prefer not to have them publicized automatically, return to Settings > Sharing, and disconnect your account(s). The icons will still remain in your sidebar.
Let me know if you have any questions.