Nokia has provided everyone with details on How to update your device in the link below.
http://europe.nokia.com/find-products/nokia-belle-update/nokia-belle-update-faq
Just follow the procedure and your device will have a smooth transition to the Nokia Belle firmware.
Some tips to follow
The Nokia Suite will download the update which a massive 303MB , so its a must that you have fast Internet connection otherwise, your update might take ages to download.
Once the update is downloaded, the Nokia Suite transfers the update to your device, the update for me very fast, under 4 minutes.
The belle OS is a such fresh outlook to your old device firmware, hope you enjoy the update.
Above is a Nokia E7 running on Belle.
