It is for loading all four layers instead of just one but maybe the attached map layer loading code will help. What problem are you having with sprites? Use spset to allocate one, spofs to move it around, and spclr to deallocate when you are done with it. You can also set animations with spanim.
Use BGLOAD with MAP0% to load your map.
EXAMPLE:
BGSCREEN 0,127,127
BGLOAD 0,MAP0%
Also, here is an example of how to use sprites.
SPDEF 0,0,0,32,32 'Create a custom definition number.
VAR SP=SPSET(0) 'Display the sprite.
SPOFS SP,200,100 'Change the sprites location
