Hello
The first thing you should do is to create an assembly. Then in Animation modul define the 'ground' and the 'bodies' .You can leave the 'gorund' by default, the bodies are the moving parts in animation. You can set this from "Body definition in animation" button on the right.
Next click on "Drag packeged components" and in the dialog choose the basic coord. system. Then move some part (X,Y,Z or around axis) and click on the "camera" button to make a snapshot, make the next move and create another snapshot. Every snapshot defines position of the elements. When you create enough snapshots click on "Create a new Key Frame sequence". In this dialog you can select snapshot and time.
Set the camera position, transparency if you want ( i suggest not to use it, because it's not very good in proE) ... and you're ready.
This was for very basic animation.I hope it will help you for the begining.
And as Jasek said you shoud learn servo motors too.Amazingresult you will achieve when you use rendered frames in your animation
Good luck
Vasil Velchev