Page does not show up under parent (new to wordpress)

Hi!

I wrote a new page and published it. Then I assigned it a parent, which is a page/item in the menu. It does not show up when I click on the parent page! I can go to the page if I type its url but ppl will have no way of finding it.

I need to be able to post many (possibly hundreds) short pages that are ads sort of craigslist style, under each menu item. So you click on the menu item and the ads show up as individual ads. I am using the attitude theme.

If I should be using a different theme or if I should be doing it as blog posts instead, let me know?

TIA