This video explains below in Linux.
What are file and directory permissions?
How to assign file and directory permissions to users, groups and others?
How to change ownership on files and directories?
How are the default permissions are provided to files and directories?
What are sudo and su and how they differ?
As part of this various commands are explained. For example chmod,chown,umask,sudo,su.
For more details about users and group management, please go through below video.
https://youtu.be/rEoIF5Z4wDM
