The manual then goes onto explain 3 different methods of withdrawing these bonuses: You have the very low risk method that uses statistically perfect blackjack techniques to withdraw bonuses safely, you have the "get loads of shot's at winning big for free" method that uses roulette and blackjack and then you have the higher risk win big but still odds in your favor method.
It's a mathematical fact that if you bet in certain ways when you are betting with casino match bonuses you have up to an 80% edge over the casino (based on £100 / $200 cash match bonus and 20x bonus turn requirements).