The style guide was created with the static site generator Middleman. It requires Ruby to be installed. If you're using a Mac, Ruby is installed by default. If you're using Windows, you'll need to install Ruby first using the RubyInstaller.
Open up your preferred command line application, change directories to the cardinal-styleguide folder, and type the following (note: $ is just a representation of a command that should be typed in the command line, don't actually put it in the command line):
$ gem install bundler
Bundler is a package manager for Ruby that manages the dependencies that will need to be installed to run Middleman. Once bundler is installed then:
$ bundle install
This will install all of the required dependencies. You can now start up Middleman:
$ bundle exec middleman
This will start up a Sinatra server running Middleman. You can now view the prototype at http://localhost:4567.