Your sentences are open to many interpretations : they are loose ends in your last sentence .
I just try . ok?
Every next level increases your winnings up to 3 times. > At every next level , your winnings will be increased to a maximum of 3 times of what it is before.
In the game you can multiple you Grand prize up to 100 times.> In the game , you have to multiply your winnings up to 100 times to win the grand prize.