What does ActionController::Routing::Routes.draw do |map| do? - ruby-on-rails

Question

I have the following code in a routes file which I haven't come across before, but need to get my head around it but I don't have a clue what's going on because I've only really used match ...
ActionController::Routing::Routes.draw do |map|
map.devise_for :users, :controllers => { :confirmations => 'confirmations' }
map.resources :sections, :only => [:index, :show]
def stories(parent)
parent.resources :stories, :only => [:index, :show], :collection => {:search => :get} do |story|
story.resources :videos, :only => [:index], :member => {:play => :get, :start_download => :get}
story.resources :images, :only => [:index], :member => {:start_download => :get}
story.resources :documents, :only => [:index], :member => {:start_download => :get}
story.resources :audios, :only => [:index], :member => {:play => :get, :start_download => :get}
end
end
stories(map)
map.namespace :manage do |client_admin|
client_admin.resources :stories do |story|
story.resources :meta_datas
story.resources :media_files, :collection => { :clone_metadata => :get }, :member => { :crop_thumbnail => :get } do |mf|
mf.resources :media_meta_datas
end
end
client_admin.resources :users, :only => [:new, :create, :index]
end
map.ftp_upload 'manage/stories/:story_id/ftp', :controller => 'manage/media_files', :action => 'ftp'
map.page ':page', :controller => 'pages', :action => 'show', :page => /terms/
map.contact '/contact', :controller => 'contact', :action => 'index'
map.resource :password_reminder
map.library_redirect '/library', :controller => 'media_files', :action => 'redirect'
map.library '/library/:media_type', :controller => 'media_files', :action => 'index'
map.press_kits '/corporate-information', :controller => 'stories', :action => 'press_kits'
map.resource :global_toolkit, :controller => 'global_toolkit', :as => 'global-toolkit', :only => 'show' do |toolkit|
toolkit.library_redirect '/library', :controller => 'global_toolkit_media_files', :action => 'redirect'
toolkit.library '/library/:media_type', :controller => 'global_toolkit_media_files', :action => 'index'
toolkit.press_materials '/press-materials', :controller => 'stories', :action => 'press_materials'
toolkit.brand_guidelines '/brand-guidelines', :controller => 'stories', :action => 'brand_guidelines'
toolkit.martini_contacts '/martini-contacts', :controller => 'stories', :action => 'martini_contacts'
stories(toolkit)
end
map.root :sections
end
When I go to the URL /global-toolkit/brand-guidelines1 it says unknown action but as far as I can figure out it should work.