Go To "My Workbench". Under the "My Websites" list is a "My Groups" list where you can edit some of your group's features. Select the site/group there.

 

social media interface -imageOnce on your group's page, select the "Edit" tab.

At the bottom of this group page, you should see a field called "Social Media Accounts". Here you will add a title (must be lower case) and the corresponding url.