Question Call canvas from a prefab (which works in singleton)? help

I am a newbie, I clarify first of all ... =)

I have a scene that when starting, an instance of a prefab is created, which is never lost since it is marked as singleton, now if I wanted to call / activate this canvas (which I mark in the image), from this scene or another, I've already been trying to refer to it, but I can't.

How can I use script to call the Canvas of the Prefab? I need to be able to do the same, that if I press on the check mark to activate canvas as I mark it in the image, let me explain?



Attach a video of what I need to do, but through code