Hi Richard,

Mongodb should be installed and running before you run the "node install" command. In some cases, the mongodb service will not automatically be run after installing; this is the case when installing on OSX. You must either manually start the mongodb service, or add a script to do it for you at startup time.

The authoring tool will automatically connect to the mongodb service if the correct settings are provided during install time. By default, the mongodb service runs with no username/password and listens on port  27017, so as long as you haven't changed that the default settings in the installer should work for you.