In Hold'em you must make the best hand possible using any combination of your two cards and the five community cards on the table.
You can use both, one or none of your own hole cards in making your best hand. Here are some rules about evaluating a winning poker hand:
Here is the official poker hand rankings. There are no exceptions to this ordering: a flush always beats a straight, and three of a kind always beats two pair.
There are no hands used in Hold'em other than the hands listed in this chart. For example, having three pairs is actually only "two pair," with the highest-valued two pair making your hand.
Poker hands must be exactly five cards and only those five cards are used to evaluate the winning hand. For example:
If the board is 2♥ J♣ Q♣ K♠ A♦
Player 1 holds T♠ 9♣
Player 2 holds T♣ 2♣
Both players hold the very same hand (a straight from ten to ace).
This means the pot is split between the two players.
The remaining cards and the fact Player 1 also has a pair means nothing - only the best five-card hand factors into deciding the winner.
If all remaining players have nothing (no pair or anything stronger), the winning hand is the hand with the highest-valued single card, meaning:
A♣ 3♥ 4♦ 6♠ 7♠ is a better hand than K♠ Q♠ J♣ 9♣ 8♦
A♣ J♥ 9♠ 8♦ 6♥ is a better hand than A♥ J♣ 9♦ 8♣ 2♠
Suits are never used to evaluate the strength of a hand.
Once you determine the winning hand, that player receives the pot. The dealer passes the dealer button to his or her left and the two players to the left of the new dealer put out their big and small blinds respectively.