You've got two goals in this game, to survive and to get as many points as you can.
You start aiming your first two darts at the current double and throw the last dart at the bull.
You get 25 points for every normal double and 50 points for bullseye.
If you miss both doubles and the 25/50 it will cost you 100 points.
Hitting the outer bull with your third dart saves you from losing 100 points but won't give you any additional points (this is a doubles game).
In normal mode if you miss and your score is zero or less, you restart the game with first double.
Finish all the doubles.
You have 3 lives. If you miss all three darts and your score is zero or less, you lose one life. With zero lives left, the game is restarted with first double and 3 new lives.