Ok, welcome to command-line-fu 101
The
command line is the interface to the operating system. By typing commands, you give orders to the system and execute operations.
Each command executes in its own environment, which is composed of a lot of different parameters and variables, the most important being the
working directory.
This is the directory in which the command will be executed ; every relative file path is relative to this working directory. The
prompt (i.e. the beginning of the command line that is fixed and written by the operating system) usually includes the working directory, in order to make it explicit.
For example, the command
copy c:\tmp\test.txt toto.txt contains two file paths : one, absolute, points to the file
c:\tmp\test.txt ; the other, relative, points to the file
toto.txt in the
working directory
The command that changes the working directory is the command
cd.
So, in your case, when you open a command line interface, the working directory seems to be
C:\users\bb ; change into the calibre library folder, for example
cd C:\Users\bb\Desktop\calibre if that's the correct path, and note that the prompt changes accordingly. Then, type the command...
Hope this helps,
David.