The best hand in poker is called a " Royal Flush". This is five cards: 10, Jack, Queen, King and Ace all of the same suit eg.
The next best hand is a Straight Flush. This is any 5 straight running cards all of the same suit eg.
Or
The highest straight flush is the straight flush that runs to the highest card (hence the Royal flush is the top hand).
For example:
Runs to the 10; so beats
.which runs to the 5.
The next best hand is Four of a Kind, or a "Poker", for example:
or
With four of a kind the fifth card only matters if all of the four cards of the four of a kind are in the community cards. Otherwise that card won't really matter, because no one will have the same four of a kind as you.
The highest four of a kind wins: in this example four 7s beats four 5s.
The next best hand is a Full House. A full house is a combination of 3 of a kind and a pair, for example:
or
The best full house is the full house with the highest three of a kind, for example:
beats
The next best hand is a Flush. A flush is any 5 cards of the same suit, for example:
The flush with the highest card in it is the winning flush. If two flushes have the same high card, then the next highest will be the decider, and if those are the same then the next highest is the decider, and so on.
The next highest hand is a Straight. This is five running cards just like a straight flush except the cards are of mixed suits. For example:
Just like a straight flush the best straight is the straight that runs to the highest card.
The next best hand is Three of a Kind eg.
The highest 3 of a kind wins. The other two cards in this hand, called the "kickers" will decide which three of a kind wins when two players have the same three of a kind. For example if two players both had three 7s, but one of them had an ace and a jack with theirs and the other player's kickers were a king and a queen then the player with the ace kicker wins. If both had the same high kicker then the second kicker would decide. If they both had the same kickers then it would be a split pot.
The next highest hand is Two Pair eg.
The player with the highest pair in the two pairs wins, and if they have the same high pair then the player with the highest second pair will win. Again here, if two or more players have the same two pair the highest kicker will decide the outcome of the hand.
The next highest hand is a simple Pair eg
If two or more players have the same pair then the kickers will determine the outcome of the hand accordingly.
If no player has any of the above hands then the highest card will determine the hand, with kickers counting accordingly in the event that two or more players have the same high card.