How can i make my garage band software respond to my psr-260

Hi everyone
I want to ask everyone for help. I recently buy a USB Midi cable to connect my PSR-260 keyboard with my macbook and use it with garageband. Garageband detect the Midi device, but does not receive any input sound from the psr-260. How can i solve this? do you know if i need a driver? where i can found it? Its possible to hook up the psr-260 with a mac?

Hugo