Open Office Draw Features?

Need help with open office. I need power point real bad because I need the basic shapes in the power point (specifically I need the edged square in basic shapes in power point) because I need to draw ER diagrams. These show realtionships in buisness, etc. I need the shapes and I downloaded open office (http://www.openoffice.org)
but when I downloaded it, I can't use it. Which icon do I use. I need the draw feature in openoffice, but instead when I download it I get another folder with other icons.
Where do I go to get the draw feature.