How to Update Samsung Galaxy S3 Software using Kies

 If you want to enjoy more out of your Samsung Galaxy S3, you need to keep it updated to its latest software updates on Kies. Samsung Kies is a tool from Samsung that lets your mobile phone get any latest sotware available software upgrades that will add  enhancements like extra speed, improved functionality and fixed for any bug issues.

To update your Galaxy S III thru Kies you only need to download it from Samsung Kies.

Kies 2.0

You must ensure these things first before you may upgrade to avoid failure issues.

• Make sure galaxy S3 battery is fully charge.
• Ensure that you have a good internet connection
• Kies will run on computer with Mac and Windows OS
• Use the supplied USB date cable with the Galaxy S3

Step 1: 
Once, you already downloaded Kies, Install and run it in your computer
Step 2:
The connect your mobile phone to your PC using USB cable
Step 3:
Just follow the onscreen instruction on Kies window. Kies will guide you through the installation process
That's It! You can now update your Samsung Galaxy S3 to any latest software updates available from Kies.

source: Samsung UK