The flop is dealt after the first betting round. Three shared cards are turned over at the same time, and every player can use them with their own hole cards. A second round of betting follows. The next community card is the turn, and the last is the river. The flop is the point where most players learn whether their hand has improved or has a draw, and it is often where the biggest decisions are made.
Example
A player holds two hearts and the flop shows two more hearts. That is a flush draw with nine hearts left among 47 unseen cards.