You may get a message about having the change the paper orientation, if so, accept the change.
The print preview should show your business card or other design in the center of a full sheet of paper.
Along the left side, you will have four buttons. Click the second one--Imposition Layout Tool. Now in the options bar, you will have a place to specify the number of rows and columns to repeat your design. For business cards, set it for 3 across and 4 down. This will give you 12 designs to the page and maximize your paper usage.