If your sprites are 16x16 pixels in size. Assuming you have created the first brush sprite, which will be cloned...
for n=0 to 9
x=n*16
y=100
spr=clonesprite(brush)
setspriteposition(spr,x,y)
next n
If you change the range that N steps through, then you change the position of the platforms - most of the time people make a map array to hold the data then use that when creating sprites - might just be setting the sprite frame, but could do a lot more, like set whether or not a sprite is solid. I think it's worth considering how you'll handle the rest of the level - always better to go at these things with a good plan.
I am the one who knocks...