Each player rolls dice and sets the scoring dice to the side. You can continue to roll however many dice you have left as long as there is a 1 or a 5 rolled. Turns end when either there is no 5 or 1 rolled, or the "Pass" button is clicked. At that point the score is totaled up.
The player that reaches the "Points to Win" total wins, unless the another player beats them in their last turn.
Click on the "Rules" button to see how the scoring works in more detail.