The idea of Omaha is to have the best hand at the end of all the rounds of betting. Omaha can be played with as little as two players, and as much as ten players. Before the deal, the two players to the left of the dealer will make the first bets. These bets are called "blind bets." The reason for these bets is to make sure there is a bet on the table for every hand played. The first person to "blind bet" is called the "small blind" and the second person to "blind bet" is the called "big blind."
The dealer deals four cards face down. The four cards facing down are not to be seen by opponents, they are "hole" cards for you to see only. After the cards are dealt, the player to the left of the player that made the "big blind bet" will make the first play. They will raise, call or fold. After this round of betting, all the money is placed into the pot.
The next round is where the dealer deals three cards face up in the middle of the table. Everyone playing in the game uses these cards to make their best five-card hand. The cards are known as the "flop cards" or the Flop. After this deal, the player to the left of the dealer will either check or bet. If you check, you do not have to bet any chips, if you bet, the rest of the players must fold, raise or call. This is the second round of betting and all money is added to the pot.
The third deal is another community card (shared by all the players like the Flop), called the Turnthe River. The final round of betting now takes place. You will bet, call, raise or fold.
After the betting, the players remaining at this point will turn over and reveal their cards and the player with the best 5 cards hand wins the pot. Turning over the cards to see who wins is called the Showdown. If there are two or more equally best hands, then the pot will be divided/split between the respective players.