Hi,

I tried the Gus-tutorial, and am stuck in part 2, the animating part.

It says to add the arm and then stay in the edit mode to add the leg, however as I understand it, you need to go to the object mode in order to add a bone. So when I do that, I end up with 2, and after mirroring even 4 different armatures...

So after that the entire explanation seems to be off, because I have 4 armatures.

What am I doing wrong?

No, to add a bone to an armature, you need to be in edit mode in the armature.