>>15556336 x 5 = 30
6 and 5 are both on the right of the factors so their product is written aligned to the right.
3 x 5 = 15, the 3 is one step to the left so the product is one step to the left.
2 x 5, the 2 is two steps away from the right
the products are written wherever you want on rows in any order which is why 2x7, 6x1 and 6x5 are on the bottom then 2x1 and 3x1 and 3x5 next, then 2x5 is third making 6x7
The black line pairs, then the medium grey, then light grey, then white. Do it however you like
There's a reason no one uses that layout for multiplying today. Very smart guy to figure it out but we've moved on from his foundation.