Taken from the Instructions:
The object of Flying Finnegan is to set up the game so that the Tank opens and "Flying Finnegan" lands in the Water Tank. To win the game, you must be the first one to do this four times.
Push the button
If you have set everything just right, the Flag Pole will raise, Flying Freddie will climb down the Flag Pole and release the marble which will roll down and hit the Tank Latch which will open the Tank. The five marbles will roll into the Marble Catch.
At the same time, the "POW" Flag will have hit the Flying Finnegan Sign causing Flying Flo and Flying Joe to whirl and twirl down the Spiral and hit the Boom Hammer which knocks the Marble into the bucket thereby moving the Long Hammer which releases, yes, Flying Finnegan!!! who will be launched through the air into....the Water Tank which will close with a ring of the bell!!!