When you start a shell, usually you'll see a simple text prompt and little else.
It may seem intimidating, but fundamentally it's just a machine that accepts input
and accepts output. It may do it a little differently than you're used to.
basic commands
cd - Change directory. This lets you navigate to different directories
pwd - Print working directory. This prints the path of the current working directory (i.e. it tells you where you are)
ls - List the files in the current directory, and (optionally) their characteristics
cp - Copy a file (or directory)
rm - Remove (delete) a file or directory
mkdir - Make directory - equivalent to the Finder's New Folder command