Each bonus is different. Generally, you'll have to wager a certain amount to complete the bonus and get your reward. Check the individual bonus rules on your Bonus Information page to know what products you can play to complete the wagering requirements.
You can also track how far your bonus has progressed on your Bonus Information page. Note that if you place a bet, the bonus only progresses after the bet is settled.
Find more information by searching for a specific bonus in the Promotion Rules section.