Firstly, you'll need to visit the Catalyst Control Center, which can be accessed by right clicking your desktop and selecting it.
The second step is to click the "AMD Eyefinity Multi-Display" tab, and then click "Create Eyefinity Display Group".
Next, you'll want to select which type of layout you'd like for your monitors. 99% of Eyefinity users will use the 3 x 1 landscape setup, which is what we've chosen to do today.
Once you've chosen which layout you want, click 'Continue' in the bottom right hand corner.
After you've clicked continue, your monitors will flicker on and off and voila - Eyefinity is enabled. It'll show you what layout you've chosen, and from here you can arrange your desktops if they're out of order (1/2/3 instead of 2/3/1, for example).
To arrange your monitors, click 'Arrange'.
Once you've done this, one of your monitors will display blue, where you'll click the corresponding monitor in CCC. Once you've done this, click 'Done'.
That's it! You're now running an AMD Eyefinity multi-display setup!