>>2032232not really sure what you're saying, but my guess is you mean layers. (?)
generally these vectors are made up of 3 main layers: lines (top layer), fill (base color) (bottom layer) and shading (shadows and highlights) (middle layer/s)
Lines usually come first and basically create the frame of the entire image
Then people either do the shading or fill, then the other, making sure to "color within the lines" these paths (nodes don't poke out or leave a transparent bit)