In more detail, each team has their own screen, and in this screen they tuck four cards in pockets numbered 1-4, letting everyone on the same team see the words on these cards while hiding the words from the opposing team. In the first round, each team does the following: One team member takes a code card that shows three of the digits 1-4 in some order, e.g., 4-2-1. They then give a coded message that their teammates must use to guess this code. For example, if the team's four words are "pig", "candy", "tent", and "son", then I might say "Sam-striped-pink" and hope that my teammates can correctly map those words to 4-2-1. If they guess correctly, great; if not, we receive a black mark of failure.
Starting in the second round, a member of each team must again give a clue about their words to match a numbered code. If I get 2-4-3, I might now say, "sucker-prince-stake". The other team then attempts to guess our numbered code. If they're correct, they receive a white mark of success; if not, then my team must guess the number correctly or take a black mark of failure. (Guessing correctly does nothing except avoid failure and give the opposing team information about what our hidden words might be.)
The rounds continue until a team collects either its second white mark (winning the game) or its second black mark (losing the game). Games typically last between 4-7 rounds. If neither team has won after eight rounds, then each team must attempt to guess the other team's words; whichever team guesses more words correctly wins.