Connect the tubes for the water to flow from the pump to the crops and livestock without being lost in the desertic road. But don't be delayed, or the plants and animals will die before the water reaches them. There's various kind of pipes, some with bonuses that give you extra points. It's not enough for you to finish building the pipeline to pump the water before the time limit: also the water must reach the water and animals before it!
Click at the tubes to make a path; when you consider it's ready, click 'PUMP IT' repeatedly, so the green indicator raises to yellow and red (to the max): this will cause the water to be pumped to the animals and plants, if you did it well.