These are the audio files for Down to the River to Pray. Download the file for your part, plus the file that is just called Down to the River to Pray, 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 soprano/alto is played as a violin and the tenor/bass is played as a bassoon, and there is the accompanying piano part. In the individual parts, all the other singing parts are silent, your part is played and the piano is quiet(ish).