How to apply Material Layer Blend

Hi, I was following the linked tutorial flatten-the-ground-surface-or-terrain-inside-a-polygon but blocked after:

  • Creating CesiumCartographicPolygon actor
  • Added to CesiumWorldTerrain the CesiumPolygonRasterOverlay component and inserting the Polygon in its polygon array field
  • Duplicating the MI_CesiumThreeOverlaysAndClipping

At this point how do I have to add my material layer blend inside the material in order to get the output of the tutorial?
Thank you