Pavestone Retaining Walls For Sale In Arizona Highland Pavestone Retaining Wall Base?

Highland Pavestone Retaining Wall Base? - pavestone retaining walls for sale in arizona

I am installing a wall 3 meters high retention Highland Pavestone. The information on this page Pavestone is limited. It says to use 6 inches of the entire base, and the burying of the first course. What kind of products should be used for the base of 6 inches? Thank you!