They stand for the Yiddish words that tell the instructions of the game. Each player puts one token in the middle. Then each player takes turns to spin the dreidel. If you do not wish to play the game with tokens you can keep score with points instead. Each player acts according to the letter left facing up when the dreidl falls to the table.
Player takes the whole pot.
Player takes half the tokens. The player adds to the pot the amount determined at the beginning of the game. They lose a turn. Player gets all the tokens in the pot. Player must put one token into the pot.