The best Audio Upload with a Rails CRUD

I try to create audio player in a specific rails New simpleform.

Just a brief message I want to publish flip flashcard (Actually I generate Hiragana) with a audio button to listen to the word with an audio player.

I am asking what is the best solution to upload audio files? Actually I try to do that with the Cloudinary video storage service.

I create a sound uploader with CarrierWave gem like this :

# encoding: utf-8

class SoundUploader < CarrierWave::Uploader::Base
  include Cloudinary::CarrierWave

  # Include RMagick or MiniMagick support:
  # include CarrierWave::RMagick
  # include CarrierWave::MiniMagick

  # Choose what kind of storage to use for this uploader:
  storage :file
  # storage :fog

  # Override the directory where uploaded files will be stored.
  # This is a sensible default for uploaders that are meant to be mounted:
  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  # Provide a default URL as a default if there hasn't been a file uploaded:
  # def default_url
  #   # For Rails 3.1+ asset pipeline compatibility:
  #   # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))
  #
  #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
  # end

  # Process files as they are uploaded:
  # process :scale => [200, 300]
  #
  # def scale(width, height)
  #   # do something
  # end

  # Create different versions of your uploaded files:
  # version :thumb do
  #   process :resize_to_fit => [50, 50]
  # end

  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
  # def extension_white_list
  #   %w(jpg jpeg gif png)
  # end

  # Override the filename of the uploaded files:
  # Avoid using model.id or version_name here, see uploader/store.rb for details.
  # def filename
  #   "something.jpg" if original_filename
  # end

end

Then In my model I call the MountUploader with this code (the object I call is sound) :

class Hiragana < ActiveRecord::Base
  belongs_to :user
  has_many :favs, dependent: :destroy

  mount_uploader :upload, ImageUploader

  mount_uploader :sound, SoundUploader

end

The upload is created in View New : Please check the picture

My Question is How do I call the Upload? I mean I put in my code this varial @hiragana.sound but could you have a look on the error picture

Thank you for your help.