Now that the Software Updater is open on your PC you can go ahead and connect your device. After it is connected you'll be able to choose your device from a dropdown box and then you'll need to enter your device's PIN Number. If you're unsure of the number, here's how to find your BlackBerry PIN.
Next simply choose the "Run" Option to begin the install process. This first option will install the drivers on your device, after which point you'll choose run once again to install the new ROM Update. That's it, you are done, it's really that simple.
It's important to note that during the update process you won't be able to use your device. If for any reason you fail to complete the ROM process you'll need to start it over once again to complete the updates before using your device again.
To avoid disruption of the process if you use a laptop then make sure it is plugged in or fully powered up before beginning the process.