Each game is composed of several rounds, which in turn involve dealing a number of cards followed by betting. This continues until there is either only one active player left in the game or when all the betting rounds have been completed. In the latter case, the game then enters the showdown to determine the winner(s).
Betting involves each player contributing an equal amount of money to the pot. This amount grows as the game proceeds and a player may fold at any time, which means they lose the money they have already contributed and are no longer eligible to win the pot.
When all players fold but one, the remaining player wins the pot. Otherwise, if the game proceeds to a showdown, the highest ranked set of cards held by a player (the highest hand) wins the pot (ties are possible, in which case the pot is split). Note that poker is full of ambiguous terminology; for example, the word hand refers both to one game of poker and to a player's cards.