Use the Custom Buttons tab to add your own custom buttons to the viewer toolbar. You can add two custom buttons that open Web pages, Web sites and intranet sites.
Show Custom Button 1/2: Formats the viewer to display the custom button you add at the tab.
Label: Defines the text to display on the face of the button.
URL: Defines the URL (Web address) to use with the button. When users click the button, they go to the Web address you specify.