Error in loading WEBrick server on Windows

I am at the beginning of the book “Ruby on Rails 3 Tutorial”; In section 1.2.5 I am trying the command “rails server”, but I am getting a very strange error:

Usage:

rails new APP_PATH [options]

Your help will be greatly appreciated,

Alejandro Barrero

I am at the beginning of the book "Ruby on Rails 3 Tutorial"; In section
1.2.5 I am trying the command "rails server", but I am getting a very
strange error:

Usage:
  rails new APP_PATH [options]

Which directory are you running the command from? You should run it
from the root of your rails application (that is the folder containing
subfolders app, config etc).

Colin