You can not land on a point where your opponent has two or more pieces already there. Having two or more pieces on a single point is known as making a point. A made point can contain as many pieces as possible. A number of made points in succession is known as a prime.
In the event of him having a single one if you land on that point you hit him and that piece goes off the board and try to get back on the board via your home board.
One of the cardinal backgammon rules is that the pieces can only move forward.
If a player can, he has to use both of the numbers rolled. If either can be done but not both the larger one must be taken. In the event of a player being unable to do either number he loses his turn.
