rule of poker

Chatting with a  friend , today's topic is something about poker, I think it's very interesting, so now , record something as follow:

Poker has a pretty strict definition in US. It's a game where players form hands of five cards and there is a hierarchy of what kinds of hands beat other hands.

Q: How many cards are in the deck you play with?
A: the deck has 52 cards.
    the cards are 2, 3, 4, 5, 6, 7, 8, 9, 10, Jack, Queen, King, Ace---13 cards;
    4 suits are spades, diamonds, hearts, and clubs

Q: What is  the rankings of hands
A: the rank is like "one pair" or "two pair", two 2s is "one pair", and two 10s and two 7s is "two pair"; Two pair beats one pair, Three of a kind beats two pair, Etc.
    the pairs are ranked according to the normal progression.  2 is lowest, Ace highest.

Q: Here are some example hands::10-10-7-J-4 versus Q-A-8-9-2;Which hand wins and why?
A: The first hand which has an one pair