The basic differences between Omaha and Texas Hold'em are these: first, each player is dealt four cards to his secret hand instead of two. The betting rounds and layout of community cards are identical. At showdown, each poker player's hand is the best five-card hand he can make from exactly three of the five cards on the board, plus exactly two of his own cards. Unlike Online Texas Hold'em a poker player cannot play four or five of the cards on the board with fewer than two of his own, nor can a player use three or four hole cards to disguise a strong hand.
Two poker players post a blind! Before the cards are dealt, two players must post a blind bet. They are called blinds, because they haven't seen their poker cards yet. There is one small bet, the Small Blind, and one big bet, the Big Blind, usually double the small blind. These bets aren't posted by anyone, but instead by the two players sitting on the left of the dealer. The task changes clockwise each round. In order to recognize the current dealer, a special chip is placed in front of the concerned poker player. This is called the Button or Dealer Button.
Now each online poker player is dealt four poker cards and so begins the first round of betting. Do you have strong enough poker cards to commit chips or money, or will you throw away your poker cards?
To keep betting rounds organized, there are a few rules to know whose turn it is. Basically, the action goes round the poker table clockwise. When one online poker player has acted, the poker player to his left can act. In the first round of betting the poker player on the left of the big blind is first to act. From the second round on, it is always the first poker player on the left of the button. Once everyone has acted all the bets are collected and placed in the middle of the poker table. This is called the pot. Whoever wins the hand wins the pot.
After the initial round of betting the dealer deals three cards face up on the poker table, so that everyone can see them. They do not belong to one particular poker player; indeed everyone can use them to create their 5-card poker hand. This is why they are called community cards.
Now begins the second round of betting, during which you can place additional money in the pot or fold. At the end of the round, the bets are collected as usual and put into the pot. Then comes the turn.
A fourth community card, the turn, is dealt on the poker table. It is also used in combination with the other poker cards to form your poker hand. The poker players who are still in the hand engage in a third round of betting, at the end of which the bets are collected and placed in the pot. After the turn comes the river.