You start off underwater as a human and aim to evolve into bigger and stronger animals to increase your chances of survival. If you find yourself being hunted you'll need to pull all of your hide and seek skills from childhood to get away, using the terrain as well as fast movements to escape to safety.
Wherever you point your mouse is where your animal will travel to. Animals that have the ability to walk across islands will jump to them if you click. When you're in the sea clicking will give a speed boost, as long as you have something in your boost bar. Animals that have special skills will perform these skills instead of speeding up when the boost bar has enough in it.