Your casino account balance is divided into a 'cash' balance and a 'bonus' balance. When your account is credited with promotional bonus credits, these credits will be added to your bonus balance. The bonus balance is the amount that you received at the casino. This amount will gradually be moved over to your cash balance once the wagering requirement shave been met. For example, if you deposit 100 credits and you qualify for and receive a bonus of 100 credits, your balance will be 200 credits. Your balance will be split: 50% in your cash balance and 50% in your bonus balance. The cash balance is pure cash that can be withdrawn from the casino at any time and whenever you want. While your game play in order to meet your WR, the money wagered on games will equate to half from your cash balance and half from your bonus balance. Should you place a bet of 10 credits, 5 credits will be used from your cash balance and 5 credits from your bonus balance. Any winnings accrued will be allocated in the same manner (50% of you winnings will be allocated to your cash balance and the other 50% will be allocated to your bonus balance). When you make a wager, it will be deducted from your cash balance first. If there is no cash balance available, then the wager is deducted from the bonus balance.
Not all casinos make it so complicated! They keep things simple and have just one balance. In other words: there isn't a separate balance for all of the different contribution of the games. So, you don't have to transfer anything from once balance to another because your casino balance includes your main cash balance and bonuses. Of course, your balance may include some bonuses that you are unable to withdraw until you have met the wagering requirements in order to release your wins.