An example of how to do it correctly.
You have 25k credits and you can bet on up to 3 different fights. So you would go and place your bets accordingly. You would also post in that vBookie thread saying that your bet(s) for the competition are in that thread. (Otherwise they may not be counted). As long as you did not bet on more than 3 fights AND your bet(s) did not exceed 25,000 credits, you will be eligible to win.
The 2014 Hit Squad (FFL)
Eddie Alvarez - Junior Dos Santos - Patricio Freire - Jessica Eye - Pat Curran