I used 5/8” or 16mm buttons I purchased at JoAnn’s.
The basic instructions are for the left boot.

The lower boot uses the same pattern instructions even thought it looks like there should be a left and then a right side. I tried flipping the right sole and then continuing on. It still looks weird.

Have to adjust for right boot cuff, where it attaches. For the girls right boot cuff I tied off row 3, then start the scallops from the opposite end so as to have the pretty pattern of the scallops facing out like the left one.