[opencms-dev] Prompting a user to login?

[opencms at astilla.co.uk]

Hi,

I'm a new user to CMS systems in general and have recently installed
OpenCms 6 to have a play with.  Although I am an experienced J2EE developer
I am finding the OpenCms 6 docs somewhat lacking - is there a quickstart
tutorial anywhere?

Anyway, my specific question is:  is there a way for a user to see a page
link in a nav menu but when they click it have them authenticate first?  I
can't seem to find a way to protect pages so that a login box is displayed.
I'm sure I'm missing something obvious but if anyone can point me in the
right direction it would be appreciated!

Thanks,
  Andrew