Virtual DJ is a complex software. In order to learn how to use it, you should check its user manual. You can find the guide, if you go to Start > All Programs > VirtualDJ and open the PDF documents. In order to open them, make sure you have the latest version of Adobe Reader installed on your PC. Also, you can find the guides on the official web page of the developer. If you have problems using the software, you can contact the developers using the Support page.