You don't install Saké Mail by itself, it comes to you as a specific servlet under the Saké framework. The Saké framework is distributed as a "web application" as defined by the Java Servlet API version 2.3 standard. Simply installing the Saké web application will install Saké Mail as a servlet called "mail" under the "sake" web application on your server.

For specific information on installing the Saké web application, please take a look at the installation section of the Saké Administrator's Guide.