Creating a basic filter is just a matter of adding the following lines of code to your controller:

class OrdersController < ApplicationController

  def index
    @orders = Order.filter(:params => params)
  end

end

And adding a filter display tags to your page: (index.html.erb)

<%= will_filter_tag(@orders) %>

If you would like to display the will_filter table, you can add the following tag right below the filter tag: (index.html.erb)

<%= will_filter_table_tag(@orders) %>