If I get into environment
The second lot of icons you circled–click on the cube icon in that group. You have the World icon currently selected.
That means you haven’t got “Use Nodes” enabled for the material, only the background.
In your screenshots you have the texture work space selected. You need to select the ball on the left and the cube on the right. like so:
My icons are in a different order due to addons but it works the same.
The left icon (the ball) is for shaders and the right icon (the cube) is for object shaders.
what addon is this?
In this screenhot the extra icon is for the Animation Nodes’ editor.