One player acts as dealer. This position is called the button and it rotates clockwise after every hand.
The two players to the left of the dealer are called the small blind and the big blind, respectively.
These two positions require forced bets of a pre-determined amount and are the only players to put money in the pot before the cards are dealt (if no ante in place).
Every player then receives two cards face down. These are called "hole" cards.
Once all hole cards have been dealt, the first betting round begins with the player sitting immediately to the left of the big blind. This player can fold, call (match the amount of the big blind) or raise.
Betting then continues clockwise, with each player having the option to fold, call the amount of the highest bet before them, bet or raise.
When the first betting round is completed, three community cards are flipped face up on the table. This is called the flop.
The second round of betting begins with the first remaining player seated to the left of the button. The betting resumes, clockwise, with each player having the option to check (if no bet in front of them), bet (or raise if a bet before them), call or fold.
When the second round of betting is finished, a fourth community card is flipped face up on the table. This is called the turn.
The third round of betting commences with the first remaining player sitting to the left of the button.
When the third round of betting is over, a fifth community card is flipped face up on the table. This is called the river.
The fourth round of betting starts with the first remaining player seated to the left of the button. The betting continues to move clockwise.

Poker Hand Ranking

Royal Flush (A-K-Q-J-T, all of the same suit)
Straight Flush (Run of five consecutive cards of the same suit - e.g. 3 4 5 6 7)
Four-of-a-kind (Any four cards of the same rank - e.g. A-A-A-A-K)
Full house (Three cards of the same rank together with two cards of the same rank: e.g. A-A-A-K-K)
Flush (Any five cards (non-consecutive) of the same suit. Note: an Ace-high flush is always the highest flush.)
Straight (Five consecutive cards with any combination of suits: e.g. 9 8 7 6 5)
Three-of-a-kind (Three cards of the same rank together with two unmatched cards: e.g. A-A-A-K-Q)
Two-pair (Two cards of the same rank together with another two cards of the same rank e.g. A-A-K-K-4)
One-pair (Two cards of the same rank: e.g. A-A-K-6-9)
No-pair (Five unmatched cards. The best non-pair high hand: A-K-Q-J-9)