-When you select backup - It will backup and make efs.img file onMyEFS_mm_dd-yyyy-hr-mm_Device IMEI folder on Int SD card, also it will create text file just to stamp time,date and device model while you created backup. Now move both file to safer place.
-When you needs to restore, put efs.img file (your backup) on root directory of Int SD card, run application and select to Restore. Once restore done, Reboot device.
Note : This application is not for just playing around, DON'T restore just to check/test application, Restore option must be used only when you really needs it.