When you are using a Microsoft DOS command window, MS-DOS works on one directory at a time. The "current" directory is indicated as part of the command prompt.
For example, the command prompt "C:\mystuff\ebooks>" means that the current directory is the "ebooks" directory which is located inside the "mystuff" directory on the c: drive.
Use the cd command to make a different directory the "current" directory ("cd" is short for "change directory").
The command can be typed as either:
cd directory
or
cd drive:directory
For example, "cd \mystuff" will make "\mystuff" the current directory. To get to the "root" (top level directory) of your c: drive, type cd \
cd directory
cd drive:directory
Make the specified directory directory (or drive:directory) the current directory.
The directory can start with a \ or be relative to the current directory. For example, if the current directory is C:\mystuff then typing cd ebooks will change the current directory to C:\mystuff\ebooks (assuming that there is in fact a ebooks sub-directory inside C:\mystuff).
Note: Each drive (c:, d:, e:, etc.) has its own current directory. That's why there is the drive:directory variation of the cd command. For example: cd e:\photos will set the current directory of the e: drive to \photos. To switch to the e: drive, you would simply type e: and press the Enter key.
cd ..
You can also type cd .. (the two dots are required) to back out one level out of the current directory. For example, if the current directory is C:\mystuff\ebooks then typing cd .. will change the current directory to C:\mystuff
cd
If you type cd without specifying a directory, the cd command will display the directory path of the current directory. Typically you will not use this variation of the cd command since the directory path is shown in the command prompt. It is more useful in batch files.