I am too stupid to see how he did the alignment.
Did he cut the transparencies to the same size and align them? Or some other way?
No I did not cut the transparencies on the same size. For example, on the top pattern one of the transparencies is smaller and the other is larger so I can align them and use scotch tape to stick the smaller pattern on the larger pattern. I aligned the top and bottom transparencies based on the dimension of the board and the holes as reference.