I dug down removing dirt approx 2 ft and lined with FRP.(type of siding material. then mixing dirt from hole with top soil and sphagum peat filled back in and used extra to make hills with cinderblock tunnels. To control ants i keep Tarro brand bait traps out always. My enclosure is surrounded with a wood fence that overlaps the FRP at ground leve and there is one inner rail approx 8 in and second several inches higher.The upper rail is where i place ant traps and secure them so do not fall or blow into enclosure.