Go into System Preferences > Keyboard and under the Keyboard tab, check of Use all F1, F2, etc. keys as standard function keys
, as in the image below. Then, you can use the Rewind function as Fn - F7 = rewind
F8 =, Play/Pause
F9 = fast forward
F10 = mute/unmute
F11 = Volume Up as Fn - F8, etc (you can then map the buttons on your mouse to these).
F12 = Volume Down