PLEASE Help! Adding themes to imovie

When I had imovie 6.0.3, i was able to add themes to imovie which allowed me to add more pictures and was easier to use. Now I have imovie 7.1 I don't see anywhere to add themes. I want the themes that are used iDVD. Has anyone used both and can you please tell me how to work imovie 7.1? All I want is to add pictures, text, ect to a theme