Hi Paul,
Those are just Custom Links in a menu: https://generatepress.com/knowledgebase/using-menus/
I just created a new menu for that section of the footer, and added the HTML for the icons into the Navigation label. Alternatively, you can use a plugin like this: https://wordpress.org/plugins/menu-icons/
Then I added a “Custom Menu” widget into the footer widget area in “Appearance > Widgets” and applied my newly created menu to it.
Let me know if you need more info 🙂