Seven-Card Stud is a popular variant of stud poker, which is a family of poker games that deal individual cards to players. As the name implies, Seven-Card Stud deals each player seven cards, that they then use to make their best five-card hand. Seven-Card Stud is the most popular Stud game, and the World Series of Poker features both Seven-Card Stud tournaments. Seven-Card Stud is also popular in mixed games: it is the S in HORSE, and the R is Razz, a popular variant of Seven-Card Stud.
Seven-Card Stud is an ante game, meaning every play puts in a small amount before cards are dealt. One player will bring in: they will be forced to double the ante based on what card they have showing. Seven-Card Stud is usually played Limit, meaning that each round of betting is in strict increments: there is a set amount that can be bet at a time, and usually a cap on the number of raises.
Seven-Card Stud is usually played as a limit game: there is a set amount that players can bet, and a set number of times they can raise (the cap). Usually, the bet size is a small amount that increases in later rounds of betting, or in certain circumstances. Casinos usually communicate the limits by naming their tables, for instance, a table labeled $1-$2 Seven-Card Stud has a lower limit of $1 and a higher limit of $2.
Unlike Hold'Em games, where action begins to the left of the dealer, in Seven-Card Stud, action in each round of betting is determined by players' cards: in the first round of betting, action is on the player showing the lowest card, who brings in, and in every round of betting after that, the player with the best showing hand is the first to act.
Players ante: everyone places a small amount (usually half the size of the lower limit). The dealer first deals two hole cards to each player, followed by one card face up (the door card). The player with the lowest door card brings in: they must double the bring-in, and they also have the option to raise. Action proceeds to the left of the bring-in. Players can check, call, raise, or fold. The dealer deals a card up to each active player (fourth street).
Action falls on the player with the strongest hand showing: whoever has the highest card or highest pair. They can either check or bet the lower limit.
Normally, betting on fourth street is restricted to the lower limit, but if the board pairs, meaning, any player has a pair showing, any player has the option to bet the upper limit. If any player does so, every subsequent raise uses the upper limit.
Action proceeds to the left, check, bet, raise or fold, with a cap of three bets. The dealer deals fifth street face up to each player. Action again falls on the player with the highest card/pair/set showing. At this point, the bet increases to the higher limit. Action proceeds to the left.
Sixth street is dealt face up. Another round of betting beginning with the player showing the highest board. Action proceeds to the left. Seventh street is dealt face down, earning it the nickname down and dirty. (It is also sometimes called the river.)
One more round of betting, again starting with the player showing the highest board. If everyone folds, the bettor takes the pot; if there is a showdown, the last person to bet shows their hand, and players to their left either show their hand to win or muck accordingly.