Sticky bit: o + t empowers the directory, and only the creator can delete the files created in the directory (command: chmod o + t directory name).
sgid: g + s establishes the permissions for the directory, and the files created in the directory belong to the group that inherits the parent directory (command: chmod g + s directory name). Delete the permissions by subtracting them.
suid: u + s is created for executable files. Whoever runs the file has the authority of the owner of the file. For example, if I run vim and the owner of vim is the root user, then I run vim as the root user. Suid is important and dangerous and cannot be given casually. (Command: chmod u + s executable file name) Delete permission can be reduced.