Interactive Materials using UMG?

So I have tried to look for interactive materials during run time and got lots of tutorials but none had what I was looking for. All the tutorials show color change using a vector parameter but I want to change a texture. Like, in this case, the floor.
Basically what I want is a Color/Texture Options UMG Menu that appears when I press a key during run time but without creating the blueprint for floor/walls.
This menu would have the texture options which I can click and select to apply.
I am stuck at the graph inside the widget blueprint. How do I make these two buttons change the texture? Need help coding this simple thing

Or if someone could tell me how to place the walls and floor back to their original position after creating blueprints, that would also do.
Attaching the images here to help understand better maybe.