You and the dealer have six cards. You play to see who has the best five-card hand. You get to see half of the dealer's hand and then if you think you have the dealer beat, you can bet more. It doesn't get any easier.
Omaha is a variant of Texas Hold'em Poker. Omaha is considered, by some, to be the hardest game of Poker to master. Of all of the different games of Poker, Omaha is for many the hardest to learn to play and the hardest to bluff in. It is played most often at fixed limits, like Texas Hold'em and pot limit.