Say we want to multiply \\(A\\) and \\(B\\), and that \\(ncols(A) = nrows(B) = k\\).

Suppose that \\(A\\) has m rows, and \\(B) has n columns.

So \\(A\\) is m-by-k, and \\(B\\) is k-by-n.

The key will be to picture \\(A\\) as a matrix of row-vectors, and \\(B\\) as a matrix of column vectors.