Appending material in your blender project file.
1. After download, extract the product .zip file to your preferred location.
2. Open your blender project and click "Files/Append" or press Shift+F1.
3. Navigate to the product .blend file that contains the materials and click on them.
4. Open the Material Folder and double-click on the material sand_shader_fine_grained/sand_shader_middle_grained/sand_shader_hard_grained you want to append or press the button "Append from Library".
You will now find the node group under the material menu.
If you have ANY problems or questions, let me know and we'll make it right