Drag the animals from the boat to the Ferris wheel.
Give everyone a ride by clicking and dragging the Ferris wheel in a clockwise circle.
When an animal is happy enough, a pink face will pop up next to it (or, even better, a pink face with a tongue sticking out). Then you can drag that animal to the red tent.
The happier the animal is, the more points you get when you put him in the red tent.
A purple face means the animal is getting impatient.
A blue face means the animal is about to give up and go away.
If the animal does go away, you will lose points.