This guide refers to the social icon links that are at the bottom of your page.
To add or change your social icon links, head over to your page and click the "Appearance" tab.
From there, scroll to the "Social Links (Bottom Icons)" section and click the "Show all social links" button.
From there, all the possible social links will be available for you to add. All you need to do is fill in what you need and it will show up. If you leave it blank, then it won't show up on your page.