Poker is a card game in which players bet into a central pot. Unlike some other games of skill, poker is almost always played with chips (representing money). Each player has the option to call a bet, raise it, or drop out of the hand. When a player drops out, they forfeit any chips that they have put into the pot so far. At the end of each betting interval, all bets are gathered into the central pot and any player who is willing to put their own chips into the pot may do so.
While luck does play a large role in the outcome of a particular hand, it is possible to achieve positive long-term expected value by playing smartly. This requires an understanding of game theory, psychology, and probability. It also requires a careful analysis of the ranges other players are representing and an ability to balance them with your own.
A common mistake among beginner players is to assume that they must play every hand they are dealt in order to maximize their chances of winning. In fact, a good percentage of hands are best folded. This will save your chips for another hand, and allow you to stay alive a bit longer. Folding is not the same as losing; in many cases, it is a very profitable decision.