To apply Windows updates manually, follow the steps below.
To install updates in Server 2019
- Open the settings app

- Go to “Update & Security” down the bottom

- Click check for updates

- Install the updates

Once the updates are installed you may need to reboot your server.

For more information visit: https://support.microsoft.com/en-ca/help/4470788/servicing-stack-update-for-windows-10
How to Install Updates on Windows Server 2019