Fitting MP3/iPhone/AUX Connection for VW Passat B6 RCD300/500 radio/CD to play MP3/Aux

How to play MP3 or aux inputs via the standard VW radio/Cd that is fitted to the Volkswagen Passat B6 model from 2005 to 2010. Later models may already have an aux socket but as this was an extra cost option it wasn't fitted to all cars even when MP3 players were becoming standard for playing music on the move. This shows how to play MP3s on the RCD300 and RCD500 players.