PBR Mixer also features access to the underlying functions which the manager uses to create PBR layers from the N-Panel in the Shader Editor. 

Installation Instructions:

To install the addon:

1. In Blender, click on Edit, then Preferences. 
2. Click on Addons, then Install. 
3. Browse to your downloaded PBR Mixer Manager.ZIP file, select it, and click Install.
4. Enable the addon.
5. The PBR Mixer Manager will appear in the Properties panel of the 3D View and Shader Node editors.