Can't select sprite in the Skinning Editor

I want to create a character with animations by using a png sprite I drew in Krita. I installed the package 2D Animation, and opened the sprite with the Sprite Editor and switched to the Skinning Editor to create bones. In the documentation (https://docs.unity3d.com/Packages/com.unity.2d.animation@2.2/manual/SkinningEditor.html) it says to double click on the sprite and every component of the sprite should be highlighted orange. However, when I double click on the sprite, the whole png is highlighted blue, but not the actual sprite in the picture. When I follow through with creating bones and adding weight the sprite does not move so the sprite and the bones are not "connected" if that makes sense. I tried it with photoshop files, and installed the package needed, but still the sprite is not highlighted which means it is not registered (I guess that is the reason). I just don't understand what is wrong. I followed several tutorial and did some research, but from what I gathered it "should just work" but it doesn't. Did I miss something? Do I need to install another package?