Giovanni's Contraption first goes into effect on December 27th, 2014. It's located in Cinder Caldera just South of Mount Cinder.
The instructions for fueling the contraption are as follows... craft the ingredients needed to add a small amount of fuel to the fuel meter. Receive rewards for each time you turn in the specified ingredients. The rewards get better as the fuel meter gets higher. Get boosts once the meter is full.
Anytime that you click on the contraption your game screen will tell you how much time you have before the quest is inactive again, the ingredients needed to fill the fuel meter, your progress, and the rewards each time you turn in ingredients. Once the time runs out your contraption will no longer be active until a new quest starts by the game makers.