This is Group SMS plugin for Handcent SMS ,you just need it install it and view the actived status from handcent settings->handcent services->handcent group sms. handcent sms will manage the actived plugins automaticthis plugin will help you extend the android limitation when groups sms ,so you can send more group sms.every plugin will add 100 sms/hour apability for you .Please Update this plugin to Version 3.0 + Handcent SMS 4.5 ,then it will support JB (Android 4.1)