In the Windows Update menu, you may see one of a few options.
If you have a button labeled Check for updates, select it; Windows will then search MBU's update servers for any necessary updates which must be downloaded and installed.
If you have a button labeled Install now, select it; Windows has already downloaded the updates, but you must begin the installation process by select selecting that button.
After updates are installed, you may be asked to restart your computer. Save any work you have not already saved and select the Restart now button. Your computer will shut down, and depending on the size of the update, may take some time to reboot.
Once your computer has restarted, check for updates again to make sure every update has been successfully applied. If so, you should see a message under your Update Status saying "Your device is update to date. Last checked: Today," followed by the time you checked for updates.