Add your social media profiles to your site visit the "Socials" tab in "Site Settings". Click on the gear button at the top right of the editor to access "Site Settings". 

Your social media appears as linked icons at the footer of each page. Clicking on each icon will open a tab with the associated social media profile.

Enter in your social media handles for all of the websites you wish your users to see. Social media fields that have not been filled in will not appear on your deployed site.