How to add submenu to an existing menu

Hi

I am working on a shared drupal web site. as a user (not admin).
In that drupal site they have created Menus Press Release, News, Events and so on.
Under the menus year are given 2010, 2009, 2008, 2007 and so on
Like this
Press Release
2010
2009
2008
News
2008
2007
2006.

Now they told me to add the pages under the Menu "Press Release" and sub-menu "2010".
i.e. whenever user clink "Press Release" year it will scroll down. and when user click on 2010 It should display the pages for Press Release in 2010.

How should I add the page under Press Release--2010.

Thanks
Pankaj Janoti