for general grevious: a,d to move, w to jump, click o to do a combo and l to slam at the opponent with all two lightsabers fo obi wan kanobi: arrows to move, up to jump, click f to use the force and s to dive in with your single blade. you can tell when you or your opponent is being beaten up, as general grevious falls to the floor as taking damage, and obi wan is pushed back.
GLITCH WARNING: do not spam an attack (its fine to spam keys) or the character gets confused and does random effects (which some times include being killed.