People think of Let It Ride as a kind of poker, but it really has almost nothing to do with poker.
The payoffs are based on poker hands, though, so you need to understand what a straight or a flush is before you play. You're dealt three cards that belong to you and the dealer places two other cards face down on the table. As soon as you look at your three cards, you have an option to withdraw your first bet. After you see this, you gauge how strong your four-card hand is and then decide whether to withdraw your second bet. It's important to remember that this second decision is independent of the first.