Hi Sai,
there are far too many things to consider for deploying the WLAN controller pair from scratch to your network which isn't possible in a forum post.
So please get a Extreme Networks partner or Extreme Networks professional service onsite to support you and also give you a short training on the system.
1-2 days should be sufficient as you've mentioned that you've already knowledge on WLAN technology.
You'd also attend the official wirless jumpstart (1day) or wirless (4days) class which are both are also available in an virtual classroom environment.
Here the link to the trainings page....
http://www.extremenetworks.com/education/courses
Kind regads,
Ron