Nessus

I have just downloaded Nessus and am trying to learn how to use it, but the documentation for its use from the command line seems to be a little thin on the ground.

Does anyone know where I can locate a decent Howto for it? The main thing is that it says that plugins that have the ability to crash remote services or hosts have been disabled and I can't seem to enable them even though it recommends that I do to make my security audit complete.

Any one able to point me in the right direction?

Cheers people.