[Phpwebsite-developers] New developper, how to start?

[Jean-Christian I. <jc...@me...>]

Sorry if this question is answered on the main web site but I could not 
find it.

A friend of mine is a PWS user and has asked me to add some 
functionality to it. Namely he would want me to have a "random pic of 
the day" function.

I'm a PHP programmer but have never used PWS. I've just installed it. 
Where should I be looking for guideline into adding functionality to PWS?

My first question is:

- Should I be writing a new module or new core functionality?

Thanks!

Jean-Christian Imbeault