[support] Rather fundamental question - how to find how site is structured, e.g. where is the home/front page defined?

[Chris G]

Well, I have now updated this Drupal 6.16 site to 6.22 and have also
updated dozens of modules which were out of date to get rid of all the
security warnings.  It was fairly straightforward once I realised that,
in the main, all that was needed was to download and unpack the relevant
module tar file and copy it over the old version.  I also read the
release notes and did any extra cache clearing etc. mentioned there.

So far so good, I have a fairly reasonable idea of how to do things on
the support/technical side now.

However I'm totally lost as to how to manage/change the content.  Well,
not entirely true, I can see how to add what Drupal calls nodes.  The
site has various ways for users to add contents in blogs, organisation
profiles, work opportunities, etc.  That's fine and I can see how they
get added to the relevant parts of the site.

The big thing I can't understand though is how the *structure* of the
site is organised, i.e. how do I find where the front page is created
and how is the hierarchy below there structured?

The "Default Front Page" in System Configuration is set to 'front'.

Can anyone point me at where I can look and learn how the site is put
together? 

Oh, the site is http://www.globaloptimists.org/ if anyone wants to take
a look at it.

-- 
Chris Green