How to create a startup module

How can I create a startup module for GlassFish 3.1.2?

Chapter 13 of the Sun GlassFish Enterprise Server v3 Application Development Guide explains in detail how to create a Lifecycle Listener Module but right at the start of the chapter states that these are deprecated and that the org.glassfish.api.Startup interface should be implemented instead.

I can't find anywhere that explains clearly how this interface should be used to implement a startup module.

Any pointers would be helpful.

Thanks.