The first player go first. Though traditionally, the first player goes with "X",
you can allow the first player to decide whether he wants to go with "X"s or "O"s.
These symbols will be placed on the table, in the attempt to have three of them in a row.
Have the second player go second.
After the first player goes, then the second player should
put down his symbol, which will be different from the symbol of the first player.
Keep alternating moves until one of the players has drawn a row of three symbols or until no one can win.
The first player to draw three of his or her symbols in a row, whether it is horizontal, vertical, or diagonal,
has won tic-tac-toe.