Assuming that you already have one AirPort Express A1264 set up to "create a wireless network".......and the second is still set to use new factory default settings......
On the iPad home screen.....
Tap Settings, then Tap WiFi
Under the heading of Setup a new AirPort Base Station, tap on AirPort Express
AirPort Setup will take care of the rest. All that you need to do is enter a device name for the new Express when prompted and click Next.
Under Easy Setup, click on the iPhone and iPad tab for more information using the link below:
http://www.apple.com/airport-express/