Hi there!
In order to view a layer in the 2D Viewport, you'll actually need to Right-Click on the layer you want to see, and select the "View Composite" option in the drop down menu. InstaMAT won't show you the most top layer of your material like Substance Painter does, which can be annoying sometimes. The tradeoff is that you have the ability to view individual layers without turning layers on or off!
