By default when in the normal catalogue view within Lightroom the two main buttons at the bottom offer import photographs or export photographs.
But what about importing and exporting catalogues; well it is in the menu system but a faster way to get to it, is to just press the option key.
With Lightroom, you often get a different set of options on the buttons when you press the option key, give it a try.
PS if your a Windows user try the Alt key.
