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 by submitting it as the next item on a list of words so far used. The next player must then do the same with this previous word.
Usually, players write down the next word by merely using the first word that comes to their mind after they hear the previous one.
Here is an example of how a Word Association game might run:
I will go first.
First word is........