The Work includes 7 movements but the practice file includes 17 tracks, each corresponding to a part sung by the desk (soprano, alto, etc …).
To play a track, simply click on the corresponding name. A second click will pause the track.
Below the tracks there is a progress bar with start/pause controls. By clicking in the bar you can repeat or go further on the track.
The title of each track indicates the page and measure in the score. This corresponds to the pages and measurements of the Peters edition. Below the progress bar there is a table that repeats this information.