The goal of Pai Gow Poker is for the player to take the seven cards that they are dealt and then create a five-card hand and a two-card hand. The five card hand must have a higher rank than the two card hand and the standard poker hand raking applies in all cases (i.e. standard poker hands for the five card hand and a pair and high cards for the two card hand).
Once each player has set their hand, then they can compare their hand to the dealer's hands. If a player has one hand higher and one hand lower than the dealer's hands, then they push the bet that they made before the cards were dealt. If a player has both hands higher than the dealer's hands, then they win their bet. If the player has both hands lower than the dealer's hands, then they lose their bet.
The only caveat to this general way of scoring is that tied hands go to the dealer, so that the house edge is present in that way. The house edge is also present in the house taking a small commission out of each pot, so they do have an edge in the long run when it comes to playing Pai Gow Poker.
There are a number of different strategy points that a person should learn if they want to play Pai Gow Poker at the highest levels, but for the most part the optimal Pai Gow Poker strategy can be approximated quite well by doing one of two things.
The first of those things, in the case of most casinos, would be to ask the dealer to set your hands according to the house way. The house way is the strategy that the dealer is required to employ in order to set their own hand and if you set your hand in that way then you are going to be using the same strategy as the dealer. Since most house way strategies are quite close to optimal, you can play the optimal strategy simply by asking the dealer to set your hands for you.
Your second choice would be to go for the highest lower hand that you could possibly make. Not only are you limited by the fact that you only have two cards, but you are also limited by the fact that the five card hand has to be of a higher value than the two card hand. If you accidentally mess this up, then you end up losing your bet automatically, so it is quite critical that you remember that the five card hand needs to have a higher poker hand value. However, if you aim at setting the two card hand as high as you legally are allowed to do, then once again you are approximating a close-to-optimal strategy in the way that you select your hands.
If you employ one of these two strategies (house way or highest two-card hand possible), then you will be off to a running start and severely reduce your learning curve when it comes to Pai Gow Poker.