How do I update software of my Galaxy Note 4 on my PC?
There are two ways in which you can get your firmware updates:
Through OTA (Over the Air): Go to Settings > About phone > Software Update. Make sure that your battery is charged to minimum 85 %.
Using an application available for PCs. It's called KIES and is available on the Samsung website. You connect the phone to PC, the software informs you about the available updates and you can proceed with the operation.