A coin can only be moved into an empty square. A coin can't jump over another coin. A player has to move when it's his or her turn. A and B keep moving their coins, in turn, until someone gets 3 in a row and wins the game. But once you start moving the coins around, it becomes a very different game.
Strategy becomes very important.
Here are a few tips about moving the coins. You can't move to just any empty square. You can only move a coin one square over. If you surround the other player's coins with yours, he can't move the trapped coin. Sometimes you can trap the other player's coins so that his only choice is to move out of the square that you want to move into.