The wagering requirement (also called "playthrough" or "rollover") is the most critical part of any bonus. Mechanically, it is a multiplier that determines how much total volume you must bet before your bonus funds are converted into withdrawable cash. This exists because bonuses are incentives for gameplay; without these rules, players could claim a bonus and immediately withdraw it without playing.
There are two main types of wagering structures: Bonus-Only, where only the bonus amount is multiplied, and Deposit + Bonus, where both your initial deposit and the bonus are included in the calculation. The latter results in a higher total amount to wager but is common in many welcome offers.
Progress is tracked in real-time. For example, if you have a wagering requirement and you bet RM10 on a slot, RM10 is deducted from your total requirement. The specific multiplier for any given offer is clearly displayed next to the promotion in your account area.