Poker is a card game in which players wager money (representing chips) that they will win the pot by having the highest-ranking poker hand. There are a number of poker variants, and each has its own rules. There are also many common features across all poker games.
Poker can be played with any number of players. However, a good number of players is ideal for creating a competitive environment. It is important for all players to understand poker etiquette, including being respectful of other players and dealers, avoiding arguments, and always tipping the dealer.
During each betting interval (as determined by the specific poker variant), one player, in turn, places a bet of one or more chips into the pot. Other players must either call that bet by putting in as many chips as the player before them, raise it by placing in more than the amount raised by the previous player, or drop out of the hand.
As a beginner, it is important to think of poker hands in ranges. You should be aware of how often your opponent will raise pre-flop and post-flop, the size of their bets, and their stack sizes (the lower their stack, the tighter they will play).
When you are in early position, you want to open with strong hands only and make sure to check behind your opponents. As you gain experience, these concepts will become ingrained in your brain and it will be second-nature to consider things like frequencies and EV estimation while playing.