JaxLUG.net

When you hold the Ctrl and Alt keys and press T (Ctrl-Alt-T) in most Linux distribution you will enter the shell window. check with your favorite Linux distribution instructions, some have shortcuts that are easier. When ou enter the shell you will notice some words and symbols like; system02:~/myspace, It means (your username) :~/ (current directory).
You best get familiar with the Shell window. Because here is where you will type most of your commands.

Shows the displays the on-line manual pages for a given COMMAND.
MAN [name] is normally the of the manual for that command, function, or file. However, if name contains a slash (/) then man interprets it as a file. To exit the manual for that command, press “q” for QUIT.

Lists all files with tin the current directory.
A slash (/) post-fixed after a name indicates that it is a directory. In this case, bar/ and foo/ are directories. Anything NOT with a slash are all files.

Change directory from current location.
You can see that the directory changes according to what you type after cd. Typing cd alone without any argument (without anything that follows it) will bring you to the home directory of the user.