Users Guide - added basic usage section

[Mike Hearn]

> Again, I'm currently working on a MAJOR update of the Guides.
> I'll incorporate these parts into my version.
> And BTW: why is it that once you decide to do some major work,
> EVERYBODY suddenly happens to come out of the eternally dark and dangerous
> and forgotten woods?? ;-)

Oops, sorry :) Well, just take it to mean that you chose a worthwhile
thing to work on. I look forward to the new guides :)

-- 
Mike Hearn <m.hearn at signal.qinetiq.com>
QinetiQ - Malvern Technology Center