Both side printing depends on the printer. It's a feature which require a hardware in the printer known as Duplexer. Which automatically turns the paper and prints on the other side. Some printer may not come with duplexer but if they support duplex printing, you can but the duplexer for the specific printer and attach it at the back of the printer.
If your printer supports duplex printing, when you click on print, click print preferences as shown in the fig 1 below.
Click on finishing tab >>
put a check on Print on both sides under document optoins section
Click Ok to close the preferences window
Click Ok to send the print job to the printer
Below is the series of images showing how to connect a duplexer.
Press the buttons to take out the back cover
Connect the duplexer in the same place