You must be an owner of assets below:
Pyramid Solitaire Template on Asset Store Pyramid 50 Layouts Add-On on Asset Store
Follow next steps to integrate layouts into the Pyramid Solitaire Template, when you imported this Add-On:
Find this folder:

Open Pyramid Layouts Import Helper scriptable object**:**

Choose Previews folder from the Pyramid Solitaire template.
Make sure that container field automatically found correct container from Pyramid Solitaire template.
Click Import Layouts button.
Enjoy!