Ok, so i have a amel motley corn snake sex yet to be determined. If i mate it with a aner corn (maybe another motley)what would i get? What do i need to get a snowball?

well, it depends on if the snake you have is heterozygous for anything... snow corns are amel AND anery, so the parents need to have both sets of genes in order to produce babies that are visually 'snow'

for example, your amelanistic would need to be heterozygous for anerythristic, and the anerythristic you breed it to would need to be heterozygous for amelanism. If the parents are motley, or het for motley, you have a chance to produce snow motleys, but it won't affect the coloring of the babies, just the patterns.