The previous tutorials were fine but, when do we start moving things? you've come to the right place. Controllers are objects than can control the behaviour of a specified object or a group of them. They are very easy to use and you can even create your own controllers too.
First I will explain some basic controllers. The simplest controller is RotationController, which rotates a node on an axis. Let's try it:
SDE.Util.Controller.IController rot;
rot = SDE.Engine.Instance.CreateRotationController(decal,new Vector3(0,1,0),(float)Math.PI/4);
SDE.Engine.Instance.AddController(rot);
It rotates on the Y axis (the plane has only one side, so when is backwards, you can't see it). But what could happen when you create another node and add it as a child? Cool. You can use hierarchies to do this kind of things. Imagine your character takes a sword, you just have to make add the sword node as a child to the hand's character.
Another interesting controller is ThirdPersonCameraController. It let's you move the camera with the mouse and keyboard in a 3rd person way. It's very useful when testing things:
SDE.Util.Controller.IController third;
third = SDE.Engine.Instance.CreateThirdPersonCameraController(cam);
SDE.Engine.Instance.AddController(third);
You can try the rest of the controllers (new ones will be added to the engine over the time) and you can make your own controllers. Just inherit from Util.IController and add them to the engine with AddController just as before. Now I would like to show you a very cool Controller, but it's so cool that it deserves it's own tutorial...