There's no schedule for adding material to the community files. Mostly stuff gets added when someone has time to create something they want for themselves. I think Sendric keeps a list of requests, and occasionally can work on something others want.
There is "help" accessible from HL and also in the editor that talks about making classes. Prestige classes are similar, and it can be useful to load an existing one in the editor and see how it was done.
In addition - Hero Lab Help:
Hero Lab FAQ,
Editor Tutorials and Videos,
Editor & Scripting Resources.