For printing options [especially pertaining to Macs at the COM], you'll need to make choices at the printer itself. As you select your print job, press "Options" found at the bottom of the screen.

For choosing how the print job is prepared, you'll notice a drop-down menu for "Duplex". Select "Simplex" for single-sided printouts. You'll also notice stapling options!

For double-sided printouts, you'll have the options of "Duplex Long Edge" or "Duplex Short Edge".