I need rules for Mah Jong Question III Online Tournament?

I understand the rules of Mah Jong. However, when I play the tournament in iWin.com everybody beats the pants off me. I don't understand what the bonus coins do. I see that sometimes people match up a bonus coin with a random tile. I don't get it. Do some tiles have to add up to a certain number instead of picking the matching tile? For example, tonight I was playing with somebody and they got over 2,500 pts in the first tiles they matched. I don't get it. Where can I find the rules for the tournament version? Thanks in advance.|||its just like memory.u just need to match tiles that arent inclosed by others. some tiles are worth more then others and the quicker you find them the more points you recive. when you get 3 pairs of the same tiles you recieve hight bonus coins