The basic ones are Omaha Poker High (Limit and No-Limit) and Omaha Poker 8 or Better (Limit and No-Limit).
Limit simply means that there is a betting limit in each game to be used in each round of betting. No Limit simply means that ye can bet whatever ye want and ye can do so  whenever ye please.
Omaha Poker High: Prior to any cards being dealt there will be the blind bet. This is when the first betting takes place. It is obviously called blind because ye are making bets before ye see any cards getting dealt.  The first deal comes out after the blind bet is completed. During this first deal ye will receive four hole cards.  These hole cards are fer ye only and cannot be viewed by any of the other players. Following the first deal, players are allowed to bet again.  Ye will always be given the option to raise, check or fold. After any betting on the hole cards is complete it is time fer the flop. This is the point when the dealer turns over the first three cards that will be shared by all players. After the flop has been dealt on casinoextra.fr then players have the option to bet again. Next comes the turn card. This is when the dealer puts out a fourth card that will be shared by all players. Following the turn card being dealt there is yet another round of betting fer players. Keep in mind that ye are not forced to bet and ye may fold at any point if ye feel that ye will not win the pot. Following the river card is the final round of betting.  Finally the player with the best five-card hand between only two of their hole cards and three of the five shared cards is the winner.
Omaha 8 or Better: Same rules as Omaha Poker High except in this game ye can split the pot. The pot must be split between the player who has the best hand and the player who has the lowest hand. Half of the pot on each hand is given to the player with the best hand. This player may also get the entire pot because a player must qualify in order to go fer the lowest hand. In order fer a player to qualify fer the lowest hand they must first have the ability to use five different valued cards and have all five be under the value of 8 (two of which must be hole cards and three of which must be shared cards from the flop, turn or river.)  Of course, this is how this version of the game acquired the name “Omaha 8 or Better”.  If a player is trying to achieve the lowest hand, then an ace can be played as a low card in order to get the lowest possible hand.  The lowest hand a player could ever get  would be A, 2, 3, 4, 5.  This hand is also called the “wheel” or the “bicycle”. This is because half of the pot goes to the player with the lowest high card in their five cards that qualify fer the lowest hand.  Fer example, a player with a 2,4,5,6,7 would have a better “low” hand than someone with an A,2,4,6,8 because the 7 is lower than the 8.  In cases that two or more players trying fer the lowest hand have the same high card, the player with the second lowest card (or third, fourth, or fifth if necessary) in their hand wins half of the pot.
