Use a WorldEnvironment node.
Docs about using it can be found here: https://docs.godotengine.org/en/3.2/tutorials/3d/environment_and_post_processing.html
Thanks, but I need further help for that. I have already found the option to set background for something else, but I cant set it to texture.
There are 7 options:
Clear Color: not good for me, plain color
Custom Color: plai ncolor, not good
Sky: not what I want
Color + Sky: not good again
Canvas: I guess this could be good, but I dont know how to use it properly
Keep: obviusly not good for me (it doesnt clear the backgroudn at all)
Camera feed: Not what I want but maybe could help
Ok I got it!
I have to use canvas, then create a canvas layer with layer less than 0 (e.g.: -1) and add the texturerect under that