If you want to display your submenu in multiple columns, you can do so with the Mega Menu feature which allows you to display menu items with an optional icon in 3, 4 or 5 columns.
To implement this, all you need to do is navigate to Dashboard > Appearance > Menus and select the menu that you want to edit. For this feature to function, you must first enable the parent menu item by clicking on the Enable Mega Menu option to determine that this menu item will be the base of the megamenu. Once in the menus page, add another menu item and assign the layout column.
Then you will need to start adding the actual menu items that are going to be displayed within the mega menu. You can easily do this by dragging and dropping these items in the desired order.
If you wish to add icons in front of the titles, you can reference the Fontello website as mentioned on page 9 in the ‘Icons’ section to see the names of the icons which you can then place in the CSS Classes field.