Poker is a card game that requires a lot of raw technical skill to win. There is a large element of luck involved, but in the long run, the best players will always win.
To play, a player must make a forced bet (the amount varies by game) and then is dealt cards. Each player then chooses whether to check, call or raise. If you raise, you must match the latest bet or fold. Betting typically happens in clockwise order. The goal of the game is to win the pot, which is the sum of all bets made by players in one hand.
A player can also bluff in the hope of convincing others that they have a good hand. This can be an effective strategy to force weaker hands out of the pot, but it is important to understand that bluffing can also backfire and cost you money.
Alex deals himself a pair of kings off the deal (not a great hand, but not a bad one either). The betting starts and Alex ‘checks’. Brad keeps two of his cards and he probably has a straight or flush. Charley keeps four cards and he is probably trying for a full house. Dennis raised earlier and he might be bluffing. He probably has a three of a kind. So, you call and put a dime into the pot.