Instantiate a cube for each grid point into the scene

Just a guess but if you dont know how to do that then did you make the grid by hand?

The simplest way to do it is using a nested for loop:

 GameObject cube;
 int width = 5;
 int height = 5;
 
 Gameobject[,] cubes = new GameObject[width, height];
 
 for(int x = 0; x < width; x++){
 for(int y = 0; y < height; y++){
 
 cubes[x, y] = Instantiate(cube,
 new Vector3(x, 0, y), Quaternion.identity);
 }
 }