These are the audio files for Joyful, Joyful. Download the file for your part, plus the file that is just called Joyful, Joyful, which has all parts.
An MP3 player should recognise the files as being part of an album called MCC July 2013.
In terms of instruments used, the file with all parts has the soprano/alto line using a violin and the tenor/bass part using a bassoon, with the accompanying piano part. In the individual parts, all the other singing parts are silent, your part is played as a violin (for soprano/ alto) or a bassoon (if tenor/bass) and the piano is quiet(ish). Watch out in the Tenor/Bass file, the piano is so quiet that is might seem nothing is happening for a long time, it will happen eventually.