Poker is a card game played by two or more players with a goal of winning the pot (the total amount of money bet in the round). It requires some luck and psychology, but also a great deal of skill.
Each player has a turn to act. During their turn, they can fold, check, bet (put money into the pot), call, or raise (bet more than the previous player). The first player to act after the dealer is known as the button. The button moves one position clockwise after each hand.
A strong starting hand is key to success in poker. However, a good flop can still defeat even the best of hands if it comes up bad. If you start with two high cards and the flop comes up with three low cards, you are in trouble and should probably fold.
Pay close attention to your opponents and learn how to read them. Some of this is done through subtle physical poker tells such as scratching your nose or playing nervously with your chips, but the majority of it is simply observing patterns in how they play the game. For example, if someone is betting all the time then you can assume they are playing some pretty crappy cards. Likewise, if someone is folding all the time then they are likely only playing fairly strong hands. This is a simple but critical principle to keep in mind. Pay attention to experienced players and study their strategies. Learning from their mistakes can help you avoid similar pitfalls in your own gameplay, while studying their successful moves can open your eyes to different ways of playing the game and expose you to innovative techniques that you can incorporate into your own strategy.