Here's how it works
Once an original word has been chosen, usually randomly or arbitrarily, a player will find a word that they associate with it and make it known to all the players, usually by saying it aloud or writing it down as the next item on a list of words so far used. The next player must then do the same with this previous word. This continues in turns for any length of time, but often word limits are set, so that the game is agreed to end after so many words. Usually, players write down the next word by merely using the first word that comes to their mind after they hear the previous one.