Poker is a card game in which players bet into a pot, or pool of money that represents the total amount of bets placed during a hand. The aim of the game is to form a high-ranking hand from the cards you receive, in order to claim the pot. Players can also place bets without having a high-ranking hand, in order to bluff and possibly win the pot by causing opponents to fold their hands.
In addition to the initial forced bets called blinds, players put money into the pot voluntarily for various reasons. Some bet because they believe that their hand is the best, while others do so for strategic purposes (such as attempting to put their opponent on a range of hands). In general, money placed into the pot has positive expected value over the long run, and the decisions players make are based on the principles of probability theory, psychology, and game theory.
The first betting round in a hand begins when each player receives 2 hole cards. A round of betting then begins, and each player must either “call” that bet by putting into the pot the same amount as the player who made it, or raise it. If a player raises they must then call any additional raises by their opponents, or drop out of the hand altogether.
If you’re in EP, for example, you should play tight and only open your strongest hands. This is because your position gives you an edge in the final pot size, since your opponents will have to call any bet you make.