Trying to make surfaces less shiny/reflective.

I made a small “airlock” using items in the SciFi Props Pack from the marketplace.
I made a new empty level (no skybox, directional light or atmospheric fog) and used just the meshes I needed and one point light.
I want to make the surfaces less shiny. I opened up the material editor and didn’t see the normal blueprint like I did when I made a material from a tutorial.
I then clicked on “Parent” in the General tab and I do see the blueprint. I found out that this is a instanced material. I don’t know how to work with instanced materials yet.

Would I change the PARAMS FOR THE METALLIC or what’s in the Metallic section of the parent material?

Here is a picture of what I’m talking about.

You probably want to adjust the “Roughness”, You could add a mult before the output to the material (end) node.
You should probably read up on the PBR workflow if you are going to do much work with materials.