When you hover over any token, you will see how much they bet and what the payout can be.
Basically, you can bet on a single, double, triple, quadruple, sextuple, 12 or 18 numbers at once, and your payout is 36/[how many numbers you bet on] TIMES your token. So a 20$ token bet on a triple (line of numbers) means IF any of them is rolled, you will get 12x20 = 240 dollars back.
But in this game, you don't bet, you control where the ball will drop, so you can decide who will win and how much.