one stupid questions (i always have problems with the blendmaps to blend it correct o:O)

bmap sand = <sand.tga>;
bmap grass = <grass.tga>;
bmap road = <road.tga>;
bmap stone = <stone.tga>;

are this the blendmaps?

also i have a question about the blendmaps

if i want the road lying over the sand for example and sometimes the sand over the road. do i just have to do it with the alpha? (white things will be shown and alpha = nothing?)

cause i often have problems what teture comes first and how i let them blend over each other ^^''