Open the file you want to print.
On the [File] menu, click [Page Setup...].
Check that the printer you want to use is displayed in [Format for], and then select the paper size you want to use in [Paper Size].
If this printer is not displayed in [Format for], select the printer you want to use.
Configure the settings, and then click [OK].
The [Page Setup...] dialog box varies depending on the application you use. For details, see the manuals provided with the Mac OS X.