General :: How To Setup Custom Ringtones On A Droid Razor Maxx

I have a droid razor maxx and have been trying to set up custom ringtones and text alerts for certain people and a guy at the verizon store downloaded two apps that have worked for some but the problem is that the custom ringtone will start and then after a few seconds be interrupted by a tweeting tone that came preinstalled on the phone that I was initially using while trying to figure out how to set some up