Just a quick answer:
When you are in the "12 hit", HOLD left mouse button, and use the arrow keys (up, down, left right) to make the hits. The longer you hold an arrow, the stronger the punch becomes.
If you HOLD the right mouse button when you do the 12 hit, you will throw the person. And when you hold the left mouse button first, and then hold the right mouse button after it (and pressing the arrow keys) you will perform kicks instead of punches. Once again, the longer you hold, the stronger the punc or kick.