Fork and cleanup of original style available at http://openptmap.org/f/
The provided views are working with the database layout used in German Mapnik style (https://github.com/giggls/openstreetmap-carto-de)
Original documentation is available in OSM Wiki http://wiki.openstreetmap.org/wiki/Openptmap