Hi!
I need modify save function: when I save a page in my CMS area, I need add a row in a new table of my db
Can you explain me where is save function? What's file name? where the exact poin?

Thanks!

The cleanest way to do this is to modify the onBeforeWrite (or on after write action of your page). http://doc.silverstripe.org/datamodel#onbeforewrite

How do you access the data from the form in onBeforeWrite? The form fields are custom and not saved in the record for the Page, but I just want to access the Form data itself and insert some rows into the DB based on that form data.

I would like to know as well.

for now i just use the $_POST to get form values, but it doesn't look like SS way

$this->record seems to be an array of the stuff from the form in onAfterWrite.