In order for it to work for you, you have to install your OS and all your programs on it. You will need to determine how much space you are using on your current hard drive to see if it can all fit on the much smaller SSD.
Generally speaking, an SSD is used for the OS and programs, since the SSD allows faster read and write access, and you would normally store simple data on the HDD, like music, video, pictures, if necessary.