Create a Class based on an Object

As the name suggests, I am new to scripting in general and have my primary education in HTML and CSS. I'm just looking for a simple example of a Class that pulls in data from an Object.

Here is the base of what I am working on. Very simplistic

# NewDeviceClass

class NewDevice
    attr_accessor :device_names
    #Create the object
  def initialize(device_names = "Mobile Device Alpha")
    @device_names = device_names

  end

  #display nickname of device
def nickname
  if @device_names.nil?
    puts "..."
  elsif @device_names.respond_to?("each")

    @device_names.each do |device_names|
      puts "Device Nickname #{device_names}"
    end
  else
    puts "Hello #{@device_names}!"
  end
end

#End Tag
end


if __FILE__ == $0
dn = NewDevice.new
dn.nickname


#List of Device Names
dn.device_names = ["windows_pc", "apple_iphone", "android", "ubuntu", "symbian"]
dn.nickname

end


I know that I created the object here, but what if I wanted to be able to pull information from an existing object?

Any help is appreciated... FYI I am using NetBeans and running the files via Terminal on Mac OSX