Depending in your Operating System (windows 7, vista or several Linux based ) when you connect the powered on device (printer - switched on) the OS will update and install drivers automatically once Automatic updates are turned on. If this does not happen you will have to go the the device manufacturers website in your case (http://www.epson.com/) select your region and navigate to the support / download page, follow the instructions provided on the website and search for your specific device unless stated otherwise. download the drivers onto your machine and install them as instructed (usually as you would any program) you may or may not be required to reboot machine. Hope you get through.. cheers.
Source(s):
A+ training guides / certified