Simply copy JABMenu to your Applications folder (or anywhere, really), and launch the application you copied to your hard drive by double-clicking its icon in the Finder. Once launched, the JABMenu icon will appear in your menubar. Just click this icon to display your contacts in various grouped menus. You can specify many options for configuring these menus from the preferences.
While just viewing your data is great, the real power of JABMenu comes from being able to act on your data simply by selecting a data item directly from one of JABMenu’s submenus. For more information on the actions that you can execute when you select a data item, see the Selection Actions section.