Description of Backgammon A program at Mac Shareware: How to Play Backgammon
The object of the game is to be the first to get all your checkers off the board.
Playing the Backgammon game

How to Play Backgammon
The object of the game is to be the first to get all your checkers off the board.
Playing the Backgammon game
Steps:
1. Set up the backgammon board.
2. Sit opposite your opponent with the board between you.
3. Throw a single die to determine who will get to move first. Roll again if both players get the same number.
4. Move first according to the roll of the dice if you rolled the higher number, but keep in mind that you must use both dice to determine your first move.
5. Number points 1 through 24 starting with the point on the upper right-hand corner farthest away from you.
6. Move in a counterclockwise direction, and notice your opponent moving counterclockwise also.
7. Move onto open points only; you aren't allowed to move onto points with two or more opposing checkers. Move checkers separately or in pairs.
8. Move all the pips shown on the dice. Play the larger number if you can only use one of the two numbers or as many of the doubles.
9. Place your opponent's checker on the bar when you hit a blot.
10. Commence bearing off when you've moved all of your checkers into the home board quadrant.

Backgammon A is a completely free software. You can free download and use it as long as you like.