Anybody know how to play mahjong yuugi?

[quarterback]

Just discovered this game and I'm curious.

Obviously it's a mahjong game and you've got to put together matching tiles in your hand, but I'm not sure about the rest of it.   Like what are the "a" "b" "c" options you get before the tiny girls roll the dice?   

And what is happening when sometimes my opponent plays a tile and it's 2/3rds height?    And sometimes other stuff happens when I discard a tile and it seems to make my opponent happy.

And what's happening at the beginning where I see a row of tiles and then they all change?  Am I seeing my opponent's hand?   

And what is the significance of the lone tile that's turned over in that short row?

And is there a way to 'call' or take a tile after the opponent discards it?

Okay, so all I really know is that I'm supposed to match tiles and I use the keyboard to discard something in my row or the one they just gave me ("n")   But I'd like to have some idea how to actually win a hand just to see some more game play.
Thanks

[Witchboard]

This is the best video Mahjong instructions I have found.

http://mahjonginmame.nm.ru/

[vorghagen]

Understandable Mahjong instructions!!!!!!
You sir, have just opened up several hundred more MAME games for me to play. I thank you.