You can add social media icons to your pages by adding the Social Media icons supplement. You can add up to 8 of the most popular social media icons and links, just add the urls for the sites you want to link to and the icon will automatically be added for you.
Look at the bottom of this page to see the placement of the icons on the left.
Here's how to add them: https://messiah.zendesk.com/hc/en-us/articles/360013086794-Adding-a-Supplement
As with all supplements, please be sure to put your office name at the beginning of the title, with a 'pipe' separating it from the title you give your supplement. For example, the web services office would name a widget like this: Web Services | Social Media. Only the words 'Social Media' will appear on your page.