what method have to use to find the object and gets the result to display... need advice

I am new to ruby on rails world, I have a common form, which includes the table and the table columns are error_id, subject, operating_system and error_details, this is common posts form for all the operating system users, And I have three different html pages also, those are "Windows", "Linux", and "Mac", In posts show page shows all the posts of all operating systems that includes windows,linux and mac, Here I wanted to user's when they click to windows link, users should get ONLY windows related posts in the windows page, and the same proceeder to linux and mac pages,

My environment details are:- Ubuntu 14.04, Ruby 1.9.3 Rails 3.2.21 Firefox 37 Please guide me sincerely I need your help,., Thanks in advance..!!