Thank you so much for installing our theme.
1. To add icon to the menu you need to go to Appearance -> Menus and fill “Icon name” field for each menu item with the name that you can get here (Font Awesome set) http://fontawesome.io/icons/. We have added one icon for example on your web-site.
2. You can create a slider with Revolution slider and then put it instead of 3 banners with Visual Composer interface.