But this guide seems outdated, because the links don't work anymore and I can't find the mentioned example scene in any of the Oculus folders (Unity package).
The guide mentioned the "Avatar SDK" so I searched for that and it looks like the "Avatar SDK" is used for network social games and shows a whole body (avatar) etc. so it seems to be something different, because I only want to show the controller with an animated hand and not the whole body and it's also for a simple (offline) single player game.
So im confused, is there any easy way (prefab or example scene) with the current version of the Unity Oculus package to get the controller and (ghost) hand with animations like in the screenshot above?
It was unclear to me also, I thought the same as you, but you can indeed use the Avatar SDK for showing animated hands/controllers in a single player game.
Have the LocalAvatar prefab under your camera holder object, and show first person, deselect 'Enable Body'... see screenshot. That's how I did it (but I'm not showing the hands only animated controllers).