Opening the Settings menu
Open the start menu and look for the settings icon on the bottom left and then click on it.
Opening Windows Update
Click on "Update & Security" this option is usually the last option of the settings menu.
Updating Windows Server
Click on the "Check for updates" button and the server will automatically search for the latest updates that are needed.
Once the server starts updating, do not restart Windows until it prompts you to restart the machine.