As you've probably guessed, the two players take turns and only move one piece at a time, but White always moves first.
The options are:
It is also illegal to move your King into check.
If a player can get out of check, but doesn't, they have made an illegal move and it has to be taken back.
If none of the above options will get the King out of check, then the King has been checkmated. The game ends there, since his capture is inevitable.
White cannot move any of his pieces, and if White moves his King it will be moving into check - which we've just said you cannot do. However, White's King isn't under any threat of capture. So what happens.
Well it's Stalemate. Since White has no legal moves he can make, and his King isn't under check, the game is a draw.
There are other ways to draw, see later.
This move has the advantages of bringing the Rook to a more active position and putting the King where he is less vulnerable to attack.
This can only occur if
In the above position neither side can castle, Black because the King is in check, and White because the White King must cross f1 which is attacked by Blacks' bishop
Many centuries ago, the rules didn't allow pawns to be moved two squares on the first move. When the rules changed, they made up this rule to make up for the fact that pawns could now speed past an advanced enemy pawn.
The pawn on b7 has not moved. If it moves to b5, the pawn on c5, on the next move only, can capture it as though it had moved only one square. This is capturing "en passant". The pawn moves to b6 and the player removes the b5 pawn. If the player chooses not to capture the pawn on that move, he loses the chance to play en-passant.
Repetition of moves
If the same position with the same player to move is repeated three times in
the game, the player to move can claim a draw. (When the right to make a
certain castling move is lost by one of the players between positions,
then the positions are considered to be different.
50 moves rules
If there are have been 50 consecutive moves of white and of black without
any piece being taken, or any pawn move, then a player can claim a draw.
This is the official tournament rule, for friendly games players often allow you to touch a piece and change your mind, but as soon as you move a piece and let go - that's your move over.
Oh yeah, this is how the board is set up at the start of a game.
Each player has two Rooks, two Knights, Two Bishops, one Queen and one King. Just like the clergy of old, who were the chief advisors of the King and Queen, the bishops stand immediately to either side of the royality. The Rooks, like the towers of castles, sit on each corner. The Queen begins the game on a square of her own colour - the White Queen on a white square and the Black Queen on a black square. The bottom right-hand corner is always white.