Missing bone editor :(

Hello everyone,

I'm new to making games and I'm having some persistent troubles already...
I'm not able to set/edit bones in my 2D platformer. When importing sprite sheets or sprite
images, the bone editor just won't appear. I watched some YT tutorials, I did everything
as it was shown and slicing my sprite sheets is no problem. But I have no options to do
anything involving bones. I reinstalled a few times on different SSDs, installed Anima2D
from Asset Store & 2D Animation from Window->Packages->Advanced->Preview Packages.
It's been hours, but I'm still not getting any of that to work. I'd be really grateful for some
help. This way I'm getting nowhere X(

Thanks & have a nice day -R