The Basics of Poker
In poker, players place money into the pot voluntarily (with the exception of initial forced bets). These bets are made on the basis of expected value and other strategic considerations such as game theory, psychology, and probability.
After the ante (amount varies by game) is placed, each player gets 2 cards face down and then the betting starts. When it is your turn, you can call (match the amount that was raised by the player to your right) or raise. If you raise, the other players will either call your new bet or fold their hands.
To win a hand, you must have a pair or better (high card breaks ties). A full house has 3 matching cards of one rank and 2 matching cards of another. A flush has 5 consecutive cards of the same suit. A straight has five consecutive cards of different suits.
Betting is based on the expected value of your hand. Generally, you want to bet when you have the strongest possible hand or to try and force weaker hands to fold. It is also common to bluff.
It is important to play only with money that you are comfortable losing. It is also a good idea to track your wins and losses. This will help you with your bankroll management and give you a feel for probabilities and EV estimation.