Well, first, you need to obtain the actual update files and there are two ways:
- Download the Software update from the SCCM console or your WSUS and select a location to download it to
- Download them from Windows Update and they will end up in the C:\Windows\SoftwareDistribution\Download\
The update itself is made of two files:
- *.ESD File
- WindowsUpdateBox.exe
Once you have these two, you can start the actual upgrade by browsing to the folder and typing in these three commands:
start /w WindowsUpdateBox /Update /PreDownload /quiet
start /w WindowsUpdateBox /Update /Install /quiet
start /w WindowsUpdateBox /Update /Finalize /quiet
Note that the upgrade process can take 30-90 minutes, depending on your hardware. You can also add /noreboot parameter for the suppressed reboot, otherwise (at least from my experience) it will trigger a reboot automatically after some time after the last command is typed in. Even after the restart, the installation can continue for some time.
These three commands can be run from a simple .cmd file or you can implement to your installation script (if you are deploying the upgrade via package) or to upgrade task sequence.