Once you’ve assigned an existing menu to the Vantage primary menu location, it’s possible to add a menu icon for each of the pages added to your menu. To make use of this feature, edit each page that’s included in your menu, when editing a page you’ll find the Menu Icon meta box in the right column. Select an icon name from the drop-down list and it’ll display next to the corresponding page in your primary menu. To see images of the icons available, check out the Font Awesome icons page.
It’s only possible to add an icon for pages in your menu, unfortunately, this functionality isn’t available for posts, custom links or categories added to your menu. If you’d like to add menu icons for those items, consider using the Menu Icons plugin. Menu Icons plugin also offers several icon libraries and many other useful options like sizing, hiding the label and adding a custom icon image.