Start by creating a menu by going to Appearance -> Menus. You can create a menu for PC and mobile.
You can add icons to each link. The Appyn theme works with the FontAwesome icons. Just look for the icon, click on it and copy the code that the web gives you in the text field of the menu.
Finish clicking on Create menu or Save menu button.
As of version 1.5.2 of the appyn theme, links can be added to the footer. To do this you must create a new menu and mark only the “menu footer” option.