In fact, if you download the docs from Atmel's website as advised by @OldSteve you'll get some Arduino samples. They're buried in Software > ATA8520-EK2-E > Arduino.zip
You can find the hello world (sending temp & voltage) on my github: GitHub - nicolsc/AtmelSigfoxShieldEx
It should work well with the 8520E, event if it's from last year
- A full tutorial for a "connected plant" using the ATA8520 evaluation kit here : http://www.instructables.com/id/Sigfox-Talking-Plant/
Let me know if it helps ... or if you need more info 