There is not really much complicated things really.
1) Enter the amount you have on your betting website.

2) Enter your multiplier. (This will be applied when you lose, if you look at the picture i have 1.5 so that means it will take my initial bet and multiply it by 1.5)

3) Enter your initial bet(Starting bet)

4) Enter % chance to win (33% chance to win means you have a 1/3 chance of winning)

It just simulates how many times you can actually lose in a row and how big chance that is to happen.