Omaha Poker is very similar to Texas Hold’em with a couple of different game-changing factors. Firstly, instead of two hole cards each player is dealt four hole cards.
Secondly, in Omaha players must make the best possible hand using exactly two of their hole cards (no more and no less) and three from the five community cards.
So if your hole cards are 3♠ 5♣ 9♦ A♥, and the community cards are 2♠ 5♥ 10♥ Q♥ K♥, you do not have an A♥-High Flush (5♥ 10♥ Q♥ K♥ A♥), as you have only used one hole card, rather than the two necessary, but instead have a pair of 5’s (5♣ 5♥ Q♥ K♥ A♥).
In Pot Limit Omaha (most popular form of Omaha Poker), the maximum a player can bet is the amount that is in the pot. For example, a $100 bet is the biggest that can be made into a $100 pot.