Samsung SCX-5639FR-XAA - Manual (Page 264)

Printing features
104 4. Special features
3 Select a binding orientation from the Two-Sided option.
4 Select the other options to use.
5 Click Print and the machine prints on both sides of the paper.
If you print more than 2 copies, the first copy and the second
copy might print on the same sheet of paper. Avoid printing
on both sides of paper when you are printing more than 1
copy.
Using help
Click the question mark on the bottom-left corner of the window and
click on the topic you want to know about. A pop-up window
appears with information about that option's feature, which is
provided from the driver.
15
Linux printing
Printing from applications
There are a lot of Linux applications that allow you to print using
Common UNIX Printing System (CUPS). You can print on your
machine from any such application.