Opening a silverlight app using VS2008 and Blend 2

Question

I am just beginning to try Silverlight. I downloaded Silverlight 3 into my VS 2008. So I began clicking New->Project then clicked on SilverlightApplication. The MainPage.xaml generated was: UserControl ..... Grid ..... Grid UserControl When I open this in Blend 2 I get all sorts of error messages such as "Grid not supported in Silverlight" etc. What have I done wrong??