1. Extract the archive in your asset libraries folder
2. Go to Edit ⮕ Preferences (Ctrl ,)
3. Clic the + button in File path > Asset library, select the Layers folder.
Choose « Append » as import method for the layers that use emptys to work properly.
4. In the shader editor, place your mouse on a corner until you see a cross like in the image below
5. Stretch a new panel on a side
6. Then clic on the editor type menu of the new panel (1) and select the Asset browser (2)
6. Then clic on all (1) and select Layerd materials (2)