Unlike some other card games where there are a lot of unavoidable forced bets, poker is mostly a game where players place money into the pot (the center of the table) on a voluntary basis. They do so either because they believe the bet has positive expected value or because they are bluffing other players.
To begin a hand, players must first place an ante (the amount varies by game) into the pot in order to receive cards. From there, one or more betting intervals take place, and the player who holds the highest hand wins the pot.
There are many strategies to play poker, but the most important thing is to understand how to read other players. This includes learning their tells (eye movements, idiosyncrasies, hand gestures, betting behavior etc). A good tip is to check when it’s your turn, then raise on strong hands. This forces weaker hands to fold and also raises the value of your own hand.
If you call, it means you will match the last person’s bet and put your money into the pot as well. If you raise, it means you will add more than the last person and other players can choose to call or fold. To fold, you must turn your cards face-down to the dealer. This is the only time you can’t see the other players’ cards. The dealer shuffles the cards, offers the deck to the player on their right for a cut and then deals cards, one at a time, until a jack is dealt.