Use the stand-alone version. Unzip to a directory of your choice and use the subsonic.sh script to start your server.
Use the Tomcat war. Install Tomcat via your package manager, and then copy the tomcat.war to it's app directory. Start Tomcat to have your Subsonic server started.
Both these ways assume that you have previously installed Java 7 and Postgresql 9.1+, as stated on the installation page.