To be able to fill the shapes with the colors you want you need to assign the colors for the shape you have drawn. You can do this by using the Inspector window where you will have all the objects listed then from the same window choose the way of the coloring (in your case it will be Fill Attribute Selectors) then just a little lower you will need to select the filling color to the one you want. You should do this while the object is selected for the settings to take effect. You can do this for every drawing area or object selected. You must select it first then assign the filling color and then the object will color itself with the one selected.
