Icons
To locate the Icons Library, go to the Left Sidebar and click on the Icons Tab. The tab will be highlighted and open the Icons Panel.
The icons library contains several icon sets such as Actions, Social, Places, Notification, etc. And for each set, it has variety icons.
Search icons and add them to the page
Browse icons library
Navigate to left Sidebar and click on Icons tab.
At the top of the panel, you will see the Icon search box and the filter icon next to the box.
As you scroll down, you will see several icon sets grouped in categories. They are collapsible and can be shown or hidden by clicking on a category name.

Search Icon
To search icons, enter an icon name or a partial of icon name. The matched results will displayed accordingly.

Filter Icon Categories
Next to the search box is the category filter icon. Select the desired categories to narrow down the icons to be browsed.

Add Icons to the page
In order to add an icon to a page, from the Icon library panel, drag and drop that icon onto the page.

Duplicate icons
There are 2 ways to duplicate an icon
Right click on the icon and select Duplicate on the Menu context
Use Ctrl/Cmd + D hotkey