Cant Access the class of newly Added Folder in another Class

I M using VS 2010 in my ASP.net project tree i added two folder named BizLayer and DataLayer and in those folder i have added some classes but i cant to access those Biz layer class in my web pages and Datalayer Class in my BizLayer class. Well i tried these things Tried to add using projectName.BizLayer --- cant able to add Trried to use in class by writing ProjectName.BizLayer.ClassInsert objInsert = new ProjectName.BizLayer.ClassInsert () -- cant able to add Tried to add by clicking on "Add Reference" -- cant able to add Kindly Help ...