NetLDAP

I have read this article : How to Authenticate With RubyNetLdap at
this adresse :

http://wiki.rubyonrails.org/rails/pages/HowtoAuthenticateWithRubyNetLdap

I am using a existing LDAP to login into my Ruby on Rail application.
Would someone be so kind to explain me how to do. I mean the steps to
proceed. I know I would have to install library, create models,
controler etc etc....But I have not found any clear and complete
documentation.

Thanks again.
Gilles TASSE