How do I add another layer to an Arnold material on Maya 2020?

I’m working with Maya 2020 modeling an inkwell. The first part was really straight forwarded, I created the model and added a Arnold standard surface to make it look like glass. I also made some ink spots on Surface Painter. My plan was to add the ink blot over my glass material
I know I can add another layer to the Arnold material with the hypershade window but I’m not sure how and I’m stuck blindly changing setting.
Can anyone help me out?