Depending on what kind of data you want to back up (SMS, contacts, pictures, music, applications), you will have to use a different application. Android OS doesn't have a backup function, so in order to back up your device, you need to use a proper application. I suggest that you visit the Android Informer website and search for an application that can help you with your problem. There are different applications that can be used for different types of data. Make sure to install and use one that suits you.