If you go to Find at the top right of this page, you can look down that menu to see Surnames. There are over 1,000 with the Rees surname. If you narrow the search to David Rees, you will find a fair number with your name. Some trace back to Wales.
Also, you can check out the Help menu by clicking on Mentors. By reading over the list and their description you can select a contact or two that can be a resource person for your genealogical interests.