Basically it's a 4-button game: A = LP, B = LK, C = HP, D = HK. Pressing buttons in different combinations will result in additional techniques.
Directional notations are also generally in this format:
.- up (u) | up+back (ub) - 7 8 9 - up+forward (uf) back (b) - 4 6 - forward (f) down+back (db) - 1 2 3 - down+foward (df) | `- down (d)
Note: These numbers can be easily referenced by looking at your keyboard "numpad". Think of it as a joystick/controller that is facing to the right. "5" is used to signify "neutral".