Start scribus-ng and set Document Layout to Single Page, set Default Unit to inches, set page Width to 3.5 inches set page Height to 2.0 inches. Install the pdfjam package, this requires texlive and the texlive-latex-recommended packages, Install scribus-ng. here is how to accomplish this with some other tools. Usually when you create business cards you want multiple cards to appear on a single sheet for printing but you want to work with just one card page when editing.
There are other options, I use scribus with the pdfjam utility and Latex, the master page feature of scribus lends itself well to this kind of thing.
