You have to choose the likelihood of a successful outcome of the upcoming draw on the playing field. Usually, this probability varies from 1 percent to 99 percent. The higher probability of win you choose your winnings will be lower.
At the same time, if you risk and set a very low percentage of win, then if you win, your income will be more in a few times.
Most sites offer the opportunity to try out the game totally free or even pay a small initial capital for the game. So you will not be hard and will not require any investment on your part to understand the rules.