There's a tutorial in the game, but I'll list the controls here just in case:
Arrow keys to walk
Hold X to run (decreases stamina)
Press Z (or W for AZERTY keyboards) to attack
Press Z with the right timing for a triple combo
Hold Z and release when your sword flashes to do a super attack
It might take a few tries to get the timing for the triple combo right, but it's not too hard.
Have fun playing! And any comments/suggestions are welcome.