Need to learn the process in which security updates are applied in Windows machines in depth.

So I need to get familiar with the process in which security updates are applied to windows machines. Like the registry files and all. I need to learn about this in depth. From where should I start? What all terms should I Google? Do I need to know any prerequisites? I am not really familiar with Windows registry files and keys and related concepts. Need as in-depth knowledge about this as possible. Any help would be appreciated. Thanks