What is a directory in Kali Linux?

Question

I watched many videos which are introduction videos to Kali Linux and all of them are talking about directories as if it is common sense, without explaining what is it's main function or why would we change directories and what are the main differences between a directory and another.

Answer 1

possibly because directories (also known as folders):

In computing, a directory is a file system cataloging structure which contains references to other computer files, and possibly other directories. On many computers, directories are known as folders, or drawers1 to provide some relevancy to a workbench or the traditional office file cabinet.

Files are organized by storing related files in the same directory. In a hierarchical filesystem (that is, one in which files and directories are organized in a manner that resembles a tree), a directory contained inside another directory is called a subdirectory. The terms parent and child are often used to describe the relationship between a subdirectory and the directory in which it is cataloged, the latter being the parent. The top-most directory in such a filesystem, which does not have a parent of its own, is called the root directory.

are in fact common knowledge ... and are not specific to Kali in any way shape or form.