In Americana poker, players compare five card hands against each other to determine who wins. A player with a Royal Flush has a better hand than a player with a Full House, for example. Below is a list of standard combinations ranked from best to worst.
Royal Flush

Five card sequence, from 10 to the Ace in the same suit. A royal flush is a combination of a flush and a straight ending in the Ace high card. So all the cards are of the same suit, consecutive and have the Ace high card. 
Straight Flush

Any five card sequence in the same suit. A straight flush is a combination of a flush and a straight. So all the cards are of the same suit, and all are consecutive. Ranking between straights is determined by the value of the high end of the straight. A royal flush is a straight flush that has a high card value of an Ace. 
Four of a Kind

All four cards of the same index. Four cards of the same value such as four jacks or four 7's represent the second strongest poker hand. This hand beats everything except a Straight Flush. 
Flush

Any five cards of the same suit, but not in sequence. A flush is a hand where all of the cards are the same suit, if each card you have is all one suit, such as 3 of Clubs, 5 of Clubs, 6 of Clubs, 8 of Clubs and King of Clubs, then you have a Flush. Don't be tricked into thinking that all five cards are the same color. The high card determines the winner if two people have a flush. 
Full House

Three of a kind combined with a pair. A full house is a combination of three of a kind and a pair. Meaning all five of your cards are a part of a set of either two or three of the same card value (eg. three 7's and two Kings). Ties on a full house are broken by the three of a kind, as you cannot have two equal sets of three of a kind in any single deck. 
Straight

Five cards in sequence, but not in the same suit. A straight is a hand where all of the cards are consecutive. There is no continuative quality to this poker hand a straight cannot wrap around meaning it is not a straight if you have a Queen, King, Ace, Two or Three. Standard poker rules state that in the case of more than one straight, the higher straight wins, In case of straights that tie, the pot is split. 
Three of a Kind

Three cards of the same value. Any three cards with the same value (eg. a 6 of Clubs, a 6 of Spades or a 6 of Diamonds) is considered to be three of a kind. The highest set of three cards wins. 
TwoPair

Two separate pairs.Two sets of two cards of equal value constitute a hand that has two pairs. As usual the pair with the higher value is used to determine the winner of a tie. 
Pair

One pair of two equal value cards constitutes a pair. 
HighCard

When the hand you are left with has no pairs, is not a straight or a flush then it's relative value is determined by the highest value card. When two players have no pairs, straight, or flush the winner of the tie is determined by the highest value card in the hand. If the highest cards are a tie then the tie is broken by the second highest card. Suits are not used to break ties. 